Inferences from an opponent's coffeehousing

[barmar]

There's a thread at BridgeWinners discussing whether a player who knows that another pair coffeehouses is obligated to report them. He says that he's able to read their mannerisms and use that to his advantage (e.g. if he leads the J from JT9xx in dummy towards AQxx in hand, and RHO hesitates, he knows that RHO is trying to make it seem like he has the King when he doesn't, so he goes up and drops the Kingleton). He wonders whether doing this is legal, or he should report the pair so that he doesn't have an illegal advantage over the field.

 

I was going to post that there's nothing in the Laws that says players have an obligation to the field. And 73D1 says that you're allowed to take inferences from opponents' mannerisms at your own risk. But then I read it more carefully, and I'm not so sure that it applies in this case. The actual wording is:

Otherwise, unintentionally to vary the tempo or manner in which a call or play is made is not in itself an infraction. Inferences from such variation may appropriately be drawn only by an opponent, and at his own risk.

 

It seems to me that "such variation" refers to the unintentional variations referred to in the first sentence. But what about intentional variations? Does this imply that we may not draw inferences from them? Law 73D2 prohibits coffeehousing, but that doesn't mean it doesn't occur. And 73F says that if the opponents are damaged from coffeehousing, the TD should adjust the score, but what if the opponents are able to take advantage of it themselves?

 

Intuitively it seems like this should be allowed, but if my interpretation is correct it doesn't seem to be allowed.

 

Am I reading it too literally?

[gnasher]

Am I reading it too literally?

Yes. You're giving the lawmakers far too much credit.

[par31]

I think it's covered by 16A2: "Players may also take account of ... the traits of their opponents, ...". And 73D1(a) just emphasizes the prohibition in 16B1(a) and 73C of the player's partner making use of the UI, and adds the additional information that the other side draws inferences at their own risk.