Fishy?

[LH2650]

Once you start Alerting your notrump as possibly containing a singleton, you will get a score adjustment (ACBL) because that agreement is illegal.

Really? Are you certain of this. Let me quote the very first item on the General Convention chart (last part of Definition 1).

 

The ACBL policy may be found in the Club Director's Handbook, or at http://www.acbl.org/learn/noTrumpwithaSingleton.html

[Cascade]

"Willingness to play" is a strange expression. With what kind of hand would you not be willing to play in notrumps?

I am not completely sure what willingness to play means but it seems to me if one of your primary purposes in open 1NT is to suggest NTs as a final strain then this certainly makes the bid non-conventional.

 

On the other hand if your 1NT bid shows something specific like "both majors" for example then although there may be some "willingness to play" NTs it is severely diminished compared with a bid whose primarly purpose is to show a reasonably balanced hand offering NTs as a possible strain.

[Cascade]

"A notrump opening or overcall is natural if not unbalanced (generally, no singleton or void and only one or two doubletons"

 

Now Generally here is meant to modify the "requirement" of no singleton or void and only one or two doubletons. This suggest that it is possible to open or overcall a natural notrump with not only a singleton but also a void as long as this is not your "general" practice. Surely it is standard these days for some 4441 patterns to be opened 1NT, and some 5431's as in this case. Many of have witnessed top players doing this in ACBL events without adjustment.

The ACBL seem to have ruled that 1% is the threshold for opening 1NT with a singleton

 

ACBL - NT with a Singleton