If I wrote the System Regulations...

[blackshoe]

It seems we can, to some extent at least, toss the "principle of full disclosure" out the window, since it suggests that it is not (or should not be) necessary to ask "the right question(s)", while Adam suggests (correctly, I think) that in practice it is necessary to do so.

[ArtK78]

Right, but here's the funny bit: experienced Moscito players can and will answer all these questions and in fact will probably answer a few of them without prompting (e.g. may contain a 5-card minor but not a 6-card minor is probably pretty standard disclosure).

 

Most experienced "Standard" players will look at you as if you were a demented child if you asked them these questions.

 

So, which players are more ethical, and what system is "better for the game"?

Pardon me for jumping into this discussion without reading all of the preceding posts, but I don't believe you phrased the issue properly.

 

While a Moscito player may, out of necessity, disclose more information with less prompting, that does not mean that he is more ethical than the Standard player who responds to your question by looking at you as if you were from Mars. It just never occurred to the Standard player that such a question was out there, so when you ask it, he is unable to even grasp the concept of how to answer the question.

 

It would be accurate to say that the Moscito player would provide you with a more complete explanation for his bid without a need for extended interrogation. But that is a consequence of a number of factors, primarily the need for the explanation due to the unusual nature of his system. As for the Standard player, his most common response - and one that is not inaccurate - is that an explanation of a bid does not need to include basic understandings that any bridge player should know. So, when I open 1♣ in Standard, a more than adequate explanation would be 12-22 HCP, three or more clubs. It would not have to include that clubs is my longest suit except when I have a balanced hand with one or 2 4-card majors and no 4 card minor or if I choose to open AKx of clubs rather than xxxx of diamonds. It would not have to include the fact that I would open 1NT if I had 15-17 HCP and a balanced hand, or that I would open 2NT with 20-21 HCP and a balanced hand. And I could go further but it could become mind numbing.

 

Does any of this omitted explanation mean that I am being unethical? Of course not.

[bluecalm]

Does any of this omitted explanation mean that I am being unethical? Of course not.

 

Well, I think that if opponents won't expect those things you are being unethical even if you have best intentions.

This is why I think things which are :

a)very complicated

b)prone to establish many unwritten agreements which people won't realize

c)prone to give UI's because it's difficult to bid in tempo facing them

 

Should be banned.

 

In standard you can expect most people know all the interferences. If you have some things in your system which change those (like weak NT or mexican 2D or if you open 1♣ with 4-4-3-2) you should explain it or at least have good convention card at the table.

Also if you played bridge in other country than US where better minor is as about as strange guest as Moscito you should explain all things you wrote about imo.

[blackshoe]

It is not unethical to follow the rules. If you don't know (or expect) that your opponents won't understand the nuances of your bidding system, it is not unethical to leave out such details. Perhaps it comes down to what you should assume about a pair of strangers who sit down at your table. Shall you treat them as rank beginners who don't have a clue that there's any way to bid other than the one they were taught? As experts who can be expected to know "everything"? I think you have to take a middle road, do the best you can to estimate what they will need to know and how best to explain it, and go from there. And if the TD gets called, and rules that you didn't explain well enough, that's not an assessment that you were unethical, only that you misjudged the situation.

[awm]

This is why I think things which are :

a)very complicated

b)prone to establish many unwritten agreements which people won't realize

c)prone to give UI's because it's difficult to bid in tempo facing them

 

Should be banned.

I don't think these things are a function of the system, but rather of what people know or are used to.

 

In fact the "unwritten agreements" are more common in "natural" systems because people who are playing artificial relay systems and such are more likely to write everything down.

 

"Very complicated" is again a matter of familiarity. The standard american 1♣ potentially contains a lot of different hand types (weak balanced, strong balanced, some three-suiters, some hands with long clubs) and explaining all the detailed inferences as to exactly what the range of strength is (and how it depends on shape) and what the criterion is for picking which minor to open on balanced hands could be quite complex. In comparison, a 1♠ opening showing "0-5 HCP any hand" is quite simple, but it's not simpler to defend...

 

"Prone to give UI" is also very familiarity dependent. If you know the system (and your defenses) well then it's easy to bid in tempo. If you don't, then it's hard to bid in tempo. Again, it's not really a function of the system so much as familiarity.

[bluecalm]

I don't think these things are a function of the system, but rather of what people know or are used to.

 

While I agree that the more people are used to the system the more smooth the bidding goes I think that alternative meanings of openings (which are usually combined with responder bidding in a way that opener assumes he guessed opener's suits) cause too many problems.

I accept that I can be wrong on this one, but where I live people often play this kind of stuff and even if they have a lot of practice with that they usually can't bid in tempo all the time and almost never give satisfying explanations.

 

In comparison, a 1♠ opening showing "0-5 HCP any hand" is quite simple, but it's not simpler to defend...

 

Yeah, but why ban something just because it gives opponents problems ?

[Dirk Kuijt]

Obviously I'm talking my book here, but I haven't seen anyone really answer the questions I raised earlier.

 

1. How do you explain your "style" adequately?

 

2. How can one ask questions without passing unauthorized information?

 

Various people have pointed out that it is hard, that it is a matter of familiarity, and that it is matter of experience. I agree.

 

But what is the answer, within the current rules? I say there is no answer.

[Bbradley62]

Do people still use the "impossible negative" in response to a strong club opening? If so, do most people include it in the explanation of the 1D response?

[steve2005]

I would to change overcalls over 1NT

pretty anything goes for a double or 2♣

but 2♦ you need to have a known suit

this shutsdown my best convention here which is to use

2♦ to show either long ♥ or long ♠

so I would like anything to be allowed over 2♦

[blackshoe]

1. How do you explain your "style" adequately?

 

2. How can one ask questions without passing unauthorized information?

1. By telling everything you know about it that is germane to the current auction.

2. One cannot. The best one can do is try to minimize it.

[awm]

Obviously I'm talking my book here, but I haven't seen anyone really answer the questions I raised earlier.

 

1. How do you explain your "style" adequately?

 

2. How can one ask questions without passing unauthorized information?

1. Fortunately, you don't have to give a complete explanation of "style." You only need to explain partnership agreements and experience. Bad players or new partnerships usually don't have these agreements or experience so there's no problem for them. Good players in an established partnership do a fine job of disclosing style when asked (to the degree that the partners know each other's style; if they don't know, then there's nothing to disclose). It is occasionally the case that specific questions need to be asked rather than just "explain the auction" though.

 

2. Behind screens there is almost never a problem with unauthorized information. Without screens, UI is just a fact of bridge, but this will be the case regardless of disclosure regulations since people have tempo, facial expressions, etc. The fact that occasionally partner ends up with UI lacking screens is not sufficient reason to radically alter the laws dealing with disclosure, since UI is a frequent problem anyway and there are sufficient laws to handle that situation adequately. It is also the case that a thorough system card and care about when/what to ask can substantially reduce the UI problem.

[nige1]

It is not unethical to follow the rules. If you don't know (or expect) that your opponents won't understand the nuances of your bidding system, it is not unethical to leave out such details. Perhaps it comes down to what you should assume about a pair of strangers who sit down at your table. Shall you treat them as rank beginners who don't have a clue that there's any way to bid other than the one they were taught? As experts who can be expected to know "everything"? I think you have to take a middle road, do the best you can to estimate what they will need to know and how best to explain it, and go from there. And if the TD gets called, and rules that you didn't explain well enough, that's not an assessment that you were unethical, only that you misjudged the situation.

When asked, I feel that you should give a full explanation. But If, instead, you take blackshoe's advice, missing out details in your initial exposition, that opponents may be too stupid to understand, then, IMO, you should still offer to go on to complete the picture, if they so wish.

 

I'm sure we suffer more damage from opponents' economy with the truth than from being blinded by their science.

 

The most annoying kind prevarication is the omission of general bridge knowledge when the director is persuaded that some esoteric local practice fits that category.

 

I wish the rule-book recommended Sven Pran's question, at the end of the auction: what can you tell about your partner's hand from his calls?

[the hog]

snipped

 

So with this rules: (sic)

-multi would be illegal

-polish club/precision/scandi club etc. would all be legal (1♦ from precision contains balanced shape)

-alternative 2suiters would be illegal

 

snipped

Alternative 2 suiters woud be illegal

Multi would be illegal

 

You have just alienated half the weekly afternoon duplicate players in any club in Australia.

Yes the multi is sooooooooo difficult to defend against I quake in fear when anyone announces the are playing it.

[bluecalm]

You have just alienated half the weekly afternoon duplicate players in any club in Australia.

Yes the multi is sooooooooo difficult to defend against I quake in fear when anyone announces the are playing it.

 

Well, in my country it's 75%+ of club players. I was just unable to think about simple rules which would eliminate what I think is bad which would allow multi.

Maybe "anything goes" is better though. Just put some rules for having convention cards/system description for strange stuff.

 

I just fear bridge would become one big td call fest full of situations like:

 

2H* - 2S - dbl** - pass

pass***

 

* = spades or 2minors

** = either penalty or t/o after 5 seconds of thought

*** = you had penalty ? guessed so !

 

I don't think coming up with rules which would catter for all possibilities is possible. I would hate it though if people start playing things which are impossible or very hard to play ethically.

Multi is not one of those things obviously. It's easy to defend, it's quite clear how people bid after it and it's probably not too good anyway. I just want simple rules and I am willing to sacrifice some stuff people play now in the name of clarity and allowing many other things which are banned now because some old ladies didn't like facing them.

[blackshoe]

When asked, I feel that you should give a full explanation.

That is what the Principle of Full Disclosure says. But people don't understand it, don't know it, and don't follow it.

But If, instead, you take blackshoe's advice, missing out details in your initial exposition, that opponents may be too stupid to understand, then, IMO, you should still offer to go on to complete the picture, if they so wish.

It was not my intent to suggest that one should deliberately set out to limit disclosure, or to imply by action (or inaction) or word that opponents are (may be) stupid, but only to say that what to disclose, and how much, can often depend on one's assessment of what the opponents need to know.

I wish the rule book recommended Sven Pran's question, at the end of the auction: what can you tell about your partner's hand from his calls?

Last time I asked that question, the response was "Huh?" and a blank look. :lol:

[the hog]

You have just alienated half the weekly afternoon duplicate players in any club in Australia.

Yes the multi is sooooooooo difficult to defend against I quake in fear when anyone announces the are playing it.

 

Well, in my country it's 75%+ of club players. I was just unable to think about simple rules which would eliminate what I think is bad which would allow multi.

Maybe "anything goes" is better though. Just put some rules for having convention cards/system description for strange stuff.

 

I just fear bridge would become one big td call fest full of situations like:

 

2H* - 2S - dbl** - pass

pass***

 

* = spades or 2minors

** = either penalty or t/o after 5 seconds of thought

*** = you had penalty ? guessed so !

 

I don't think coming up with rules which would catter for all possibilities is possible. I would hate it though if people start playing things which are impossible or very hard to play ethically.

Multi is not one of those things obviously. It's easy to defend, it's quite clear how people bid after it and it's probably not too good anyway. I just want simple rules and I am willing to sacrifice some stuff people play now in the name of clarity and allowing many other things which are banned now because some old ladies didn't like facing them.

No you misunderstood. The lols play these things in Australia - seriously! They would not be happy about having their conventions banned.

[fred]

It's easy to defend, it's quite clear how people bid after it

You are wrong about this.

 

Multi is not easy to defend against and one of the main reasons for this is because there are many ways that people bid after it, especially in competition.

 

For example, when Multi gets DBLed, there are several reasonable ways to define both Pass and RDBL by the responder to Multi (to say nothing of all the other actions that he/she might take). Coming up with sensible meanings for various calls by the 4th hand will be largely a function of what Pass and RDBL happen to mean for the particular opponents you happen to be facing.

 

Just getting the first round of bidding covered is far from trivial. If you want to do this properly, there are a LOT a sequences to discuss (and bidding effectively in many of these sequences requires agreements that are both unintuitive and artificial). Some of the world's leading bridge coaches have actually made a serious effort to do this properly. The defenses they ended up with consist of a lot (well over 10 if I recall correctly) typewritten pages.

 

Please note that I am not telling you this to try to justify the fact that Multi is not allowed in most ACBL events - I personally think it should be allowed in several contexts where it currently illegal.

 

The reason for this post is to attempt to counter some widely-held misconceptions like "multi is easy to defend against" and "you won't have any problems if you rely on just a few simple meta-agreements".

 

Statements like these are simply not true. Those who argue "it must be easy since people in my club are comfortable with it" are missing the point - comfort does not imply effectiveness.

 

Fred Gitelman

Bridge Base Inc.

www.bridgebase.com

[Dirk Kuijt]

Let me give you a simple situation. You are West, and South deals, and the opponents have bid the exiting and unusual: (1C)-P-(1H)-P-(1NT)-P-P-P.

 

You have:

KTxx

xxx

Kxx

Qxx

 

You lead a spade from KTxx, and the dummy comes down with:

xxx

Axxx

xx

Kxxx

 

Declarer wins the Queen, leads a club to the King, and a club to his Jack and your Queen. Your partner's carding shows that opener has 4 clubs. Do you shift to diamonds?

 

Against me, you probably should. I should have 3=3=3=4 for this auction, since I didn't raise hearts, didn't bid spades, would open 1D with 4-4 in the minors and a balanced minimum hand, so I'm likely to be 3=3=3=4. Against Frank Stewart, a diamond shift is much more dangerous, since he, as declarer, might be (23)=4=4, since he opens 1C with a minimum balanced hand. If declarer has AQ (tight) of spades, then a spade continuation will likely beat the hand. If declarer has AQJ of spades, then a spade continuation is, shall we say, "unwise".

I'm not enough of an expert to fully analyze this, or almost any situation, but it is clear to me that if you know what declarer has (i.e. declarer's agreements are) you are better off than otherwise, and getting that information is difficult at best, and impossible at worst (the unauthorized information situations are decreased by screens, but not eliminated.)

 

Even if some better analyst than I can show that a diamond shift (or spade continuation) is clearly right regardless of the opponent's agreements, my point is:

 

1. The defense will do better with full disclosure than without it.

 

2. Full disclosure is rare, if not impossible.

 

3. What people think of as full disclosure is far from that; rather it assumes a large body of "standard" agreements, which may not, in fact, be all that "standard". This is, perhaps, acceptable if your opponents do have the same standard agreements, but it violates both the spirit and letter of the law if they don't. (A major problem is, if the opponents don't have the "standard" agreements, then they are unlikely to complain. They are the outsiders, since they are non-standard. Some, of course, will still ask, or complain if the explanation is inadequate, but, in general, outsiders keep their mouths shut. One consequence of this is that one can not conclude that since there are few people who complain that our rules are just fine. No. Outsiders don't complain, in general. They just go away quietly, and don't show up in statistics.)

[Free]

When asked, I feel that you should give a full explanation.

That is what the Principle of Full Disclosure says. But people don't understand it, don't know it, and don't follow it.

But If, instead, you take blackshoe's advice, missing out details in your initial exposition, that opponents may be too stupid to understand, then, IMO, you should still offer to go on to complete the picture, if they so wish.

It was not my intent to suggest that one should deliberately set out to limit disclosure, or to imply by action (or inaction) or word that opponents are (may be) stupid, but only to say that what to disclose, and how much, can often depend on one's assessment of what the opponents need to know.

I wish the rule book recommended Sven Pran's question, at the end of the auction: what can you tell about your partner's hand from his calls?

Last time I asked that question, the response was "Huh?" and a blank look. :)

There is a big difference in giving a full explanation and giving every single detail you know. For example, MOSCITO 1♠ opening can be explained in several ways:

- 9-14, unbal with 4+♦, may have longer ♣

- 9-14, 6+♦ or 4+♦ with at least 9 cards in the minors

- 9-14, singlesuited ♦ or 2-suited minors or 6♦-4M

- 9-14HCP, denies a 5 card Major, shows singlesuited ♦ with at least a 6 card or 2-suited minors, at least 5-4 in which case you can have longer ♣ or 6+♦-4M, 6+ slam points, slam points mean A=3, K=2 but singleton K doesn't count, Q=1 but singleton Q doesn't count, and if you hold 10+ cards in 2 suits you get another slam point, oh, and when singlesuited with 6♦322 it's unsuitable for a 1NT opening, so you'll have at least 2 weak short suits. Short in this case means doubleton or tripleton.

 

The first one is short, shows clearly what you have told to partner and it's complete.

The second one is getting detailed and people will need extra explanations about the minor 2-suiter (can you have longer ♣ for example).

The 3rd shows every possible hand type in detail, but since you have 3 types opps will ask to repeat this once more.

And guess what, if you give the 4th explanation you'll have to explain it 25 times and opps still won't have a clue what to expect. It is the most complete explanation you can give, but it's useless in practise.

 

Imo the first explanation is the best. Do they realy need to know that 4M-5♦ is not possible at this point? Let the auction continue, if opener shows a 4 card M you can explain this as 6+♦ and 4M because it's now applicable.

[helene_t]

Those who argue "it must be easy since people in my club are comfortable with it" are missing the point - comfort does not imply effectiveness.

Dunno. Consider the issue:

What does

(2♦)-x-(xx)-pass

mean? Does it depend on the meaning of xx?

 

Some partnerships will know. Of those who don't know, some won't know either what

(2♥)-x-(xx)-pass

means.

 

For a serious partnership it is obviously easier to make solid agreements about how to defend the natural weak twos, but it wouldn't surprise me if casual partnerships and inexperienced players have fewer misunderstandings when defending multi. For example, the fact that you in many situations don't have a bid which is obviously a cuebid makes life more difficult for the serious partnerships, but many club players wouldn't know what a cuebid means anyway.

 

Also, if you double multi, partner is often not under pressure to bid, so there is less need for Lebensohl. Again, for serious partnerships this may be no big deal since they know how to use Lebensohl, but many club players don't play Lebensohl, don't know whether they play it or not, or they try to play it but don't know how it works.

 

Having played for 7 years at a club full of very bad players most of whom play multi but none (literally!) of whom have any specific agreements about how to defend it, I would say that it inflicts less misunderstandings on defenders than on the multi-players themselves, and also that it inflicts less misunderstandings and major misjudgments on the defenders than natural preempts do.

 

That said, I think many of the better club players who would have been able to take advantage of the weaknesses of multi and get better results defending than they would defening a natural weak two if they bothered to make some good agreements about defense against multi, suffer from the fact that they don't make such agreements and therefore probably just get about the same results against multi, while in a sense they have the "right" to better results when opps play inferior methods, as I consider multi to be.

 

Also, I think multi is a problem for noobs because they don't understand the explanation (that the explanation is inadequate doesn't help, but noobs wouldn't understand adequate explanation either), or they get paralyzed because they spend too much mental energy on trying to grasp what 2♦ means.

[Free]

It's easy to defend, it's quite clear how people bid after it

You are wrong about this.

 

Multi is not easy to defend against and one of the main reasons for this is because there are many ways that people bid after it, especially in competition.

 

For example, when Multi gets DBLed, there are several reasonable ways to define both Pass and RDBL by the responder to Multi (to say nothing of all the other actions that he/she might take). Coming up with sensible meanings for various calls by the 4th hand will be largely a function of what Pass and RDBL happen to mean for the particular opponents you happen to be facing.

 

Just getting the first round of bidding covered is far from trivial. If you want to do this properly, there are a LOT a sequences to discuss (and bidding effectively in many of these sequences requires agreements that are both unintuitive and artificial). Some of the world's leading bridge coaches have actually made a serious effort to do this properly. The defenses they ended up with consist of a lot (well over 10 if I recall correctly) typewritten pages.

 

Please note that I am not telling you this to try to justify the fact that Multi is not allowed in most ACBL events - I personally think it should be allowed in several contexts where it currently illegal.

 

The reason for this post is to attempt to counter some widely-held misconceptions like "multi is easy to defend against" and "you won't have any problems if you rely on just a few simple meta-agreements".

 

Statements like these are simply not true. Those who argue "it must be easy since people in my club are comfortable with it" are missing the point - comfort does not imply effectiveness.

 

Fred Gitelman

Bridge Base Inc.

www.bridgebase.com

I agree with you that there are some situations where it's difficult to defend against a multi. Probably everyone I know has encountered some problem hand after a multi opening, but most of the time we manage to get to the correct contract. So it's acceptable.

 

What is the difference between this and a 1NT opening? You don't get to your best contract everytime, does this mean it's difficult to defend against?

A few weeks ago my partner has a 3=3=3=4 with 22HCP in 4th seat, his LHO opened 1NT and responder bid 2♦. This was just a problem hand...

[nige1]

I wish the rule book recommended Sven Pran's question, at the end of the auction:

"what can you tell about your partner's hand from his calls?"

Last time I asked that question, the response was "Huh?" and a blank look. :)

Let me give you a simple situation.  You are West, and South deals, and the opponents have bid the exiting and unusual: (1C)-P-(1H)-P-(1NT)-P-P-P.

You have: KTxx xxx Kxx Qxx

You lead a spade from KTxx, and the dummy comes down with:

xxx Axxx xx Kxxx

Declarer wins the Queen, leads a club to the King, and a club to his Jack and your Queen.  Your partner's carding shows that opener has 4 clubs.  Do you shift to diamonds?

Against me, you probably should.  I should have 3=3=3=4 for this auction, since I didn't raise hearts, didn't bid spades, would open 1D with 4-4 in the minors and a balanced minimum hand, so I'm likely to be  3=3=3=4.  Against Frank Stewart, a diamond shift is much more dangerous, since he, as declarer, might be (23)=4=4, since he opens 1C with a minimum balanced hand.  If declarer has AQ (tight) of spades, then a spade continuation will likely beat the hand.  If declarer has AQJ of spades, then a spade continuation is, shall we say, "unwise".

I'm not enough of an expert to fully analyze this, or almost any situation, but it is clear to me that if you know what declarer has (i.e. declarer's agreements are) you are better off than otherwise, and getting that information is difficult at best, and impossible at worst (the unauthorized information situations are decreased by screens, but not eliminated.)

Even if some better analyst than I can show that a diamond shift (or spade continuation) is clearly right regardless of the opponent's agreements, my point is:

1.  The defense will do better with full disclosure than without it.

2.  Full disclosure is rare, if not impossible.

3.  What people think of as full disclosure is far from that; rather it assumes a large body of "standard" agreements, which may not, in fact, be all that "standard".  This is, perhaps, acceptable if your opponents do have the same standard agreements, but it violates both the spirit and letter of the law if they don't.  (A major problem is, if the opponents don't have the "standard" agreements, then they are unlikely to complain.  They are the outsiders, since they are non-standard.  Some, of course, will still ask, or complain if the explanation is inadequate, but, in general, outsiders keep their mouths shut.  One consequence of this is that one can not conclude that since there are few people who complain that our rules are just fine.  No.  Outsiders don't complain, in general.  They just go away quietly, and don't show up in statistics.)

Examples like Dirk's occur many times a session. At the end of the auction, if you ask the Sven Pran question

"what can you tell about your partner's hand from his calls?"

and opponents answer honestly, then you will receive the necesary information.

 

Blackshoe's experience with the Sven Pran question shows why it should be recommended in the law book:

• Otherwise, prevaricators may question the legality of the Sven Pran question.
  For example, the "I'm not here to teach you Bridge" brigade.
  
• Unless the Sven pran question is in common use, players won't become adept at asking or replying to it.
  

[bluecalm]

Multi is not easy to defend against and one of the main reasons for this is because there are many ways that people bid after it, especially in competition.

 

Why "difficult to defend" should dictate the law? If it's easy to understand for opponents and it's easy to have some meta agreements to reasonably deal with it I don't see reason for banning other than comfort of some today players in some countries (mainly USA).

 

The reason for this post is to attempt to counter some widely-held misconceptions like "multi is easy to defend against" and "you won't have any problems if you rely on just a few simple meta-agreements".

 

Statements like these are simply not true. Those who argue "it must be easy since people in my club are comfortable with it" are missing the point - comfort does not imply effectiveness.

 

Even semipro/pro pairs here don't have much agreements against multi. Those are great players, they don't complain about efficiency of their defense to multi at all and they face it in every tournament and match they play because multi here is default (it's in very first bidding system people learn and most beginners/recreational players/old players play it; rest usually play Wilkosz which is much more difficult to defend than multi).

I wonder if the coach you mention plays/played vs multi every tournament/match. While it may be true that it's difficult to come up with "optimal" defense. It's very easy to come up with defense which makes pair playing multi worse off than the one playing weak twos on hands when they come up.

[jeffford76]

Do people still use the "impossible negative" in response to a strong club opening?  If so, do most people include it in the explanation of the 1D response?

In my one precision partnership 1C - 1D was always explained as "Usually 0-7, but could be a good 4441 hand". I would think this would be normal if you're playing impossible negatives.

[Fluffy]

Multi is not easy to defend against and one of the main reasons for this is because there are many ways that people bid after it, especially in competition.

 

Why "difficult to defend" should dictate the law? If it's easy to understand for opponents and it's easy to have some meta agreements to reasonably deal with it I don't see reason for banning other than comfort of some today players in some countries (mainly USA).

The problem is those meta agreements. Most of my meta agreements are based on having a cuebid avaible. I am very comfortable playing in my country where 2♦ is strong or weak 2 in diamonds and 1NT is always 15-17. However I lose a big lot of points when moving outside and facing 2♦ multi and weak NT because that cuebid we always had before is no longer avaible and our metagreements don't do well.

 

I made a quick poll about what a simple sequence opposite multi meant, and it was almost a 50% split, shows you that meta agreements aren't that easy.

 

I don't mean banning multi is the answer at all, kinda the contrary, best for me would be to face multi openings and something rare all the time, then I would have experience and less problems.