Mistaken alert
From this afternoon's session:
EW play ordinary Stayman over a 2NT opener.
The bidding goes:
W: 2NT announced as 20-22
E: 3C - alerted by W. W has forgotten they are only playing ordinary Stayman and thinks they are playing 5-card Stayman (E realises this).
W: 3D.
Should E alert? In theory she should not do so (since that is the correct action after a normal Stayman 3C over 2NT), but by not doing so she may alert W to his mistake. If she alerts, W is non the wiser, but she is using UI.
What should E do if opponents ask about the 2D bid? Should she mention that W has mis-alerted, or just say "no four card major"?
Does it make any difference if they had a misunderstanding over what they were playing (i.e. no commonly agreed system)?
Comments
Shoul East Alert? : Answer No: Blue Book 4G2. Opponents are only entitled to know your partnership agreements. If East Alerts then opponents may think that West is showing a 4-card major.
What should E do if opponents ask about the 3D bid? Explain as denies a 4 card major. That is the partnership agreement. (East may not of course bid on the knowledge that West has replied to 5-card Stayman - that is UI)
At the end of the auction (or possibly earlier by West if he realises he has given a wrong explanation) the director must be called. There is going to be UI and MI floating around and an adjusted score may have to be awarded.
If there is no commonly agreed system then opponents should be made aware of this. (This will probably happen automatically when East calls the director at the end of the auction and tells opponents that West should not have alerted 3C)
A forgotton system call is not 'no commonly agreed system' BTW. If east and west had not discussed this sequence because each knew that "everyone does ... after 2NT' then that is 'no partnership understanding. If they had agreed to play Stayman and West forgot then that is just a misbid (assuming it can be proved to be so).
Note that there is already misinformation, since West alerted, rather than announcing "Stayman", and this in itself might possibly give rise to the need for an adjusted score.
As for the rest... as weejonnie states.
Note also that after such a sequence as 2C-2D-2NT-3C, the 3C bid should always be alerted and not announced, regardless of whether it's ordinary Stayman or some variant.
Opponents are entitled to correct alerting of and information about partnership agreements, not to correct information about the contents of hands. As weejonnie says, the agreement is "no major" which is not alertable. If E alerts, the opponents are entitled to assume that the bid is alertable, i.e. that whatever it might mean, it does not mean "no major". (The combination of an alert of 3 !c and no alert of 3 !d actually suggests a Baron sequence, but that possible misapprehension on the part of N/S arises from the MI from W's alert, not from any MI from E's correct failure to alert).
When partners are on a different wavelength, and one alerts or doesn't alert in a way that is unexpected to the other, UI is inevitable. Providing UI, however, is not of itself an infraction: it is acting on it that is the infraction. Providing MI is, however, an infraction. E can do nothing about the MI that W has already provided by alerting rather than announcing the response, but she can avoid compounding the problem by giving MI about the agreed methods. (At the end of the hand she can of course say something along the lines of "We have agreed to play normal Stayman so 3 !d denies a major; however partner's alert suggests that he thinks that we are playing some kind of 5-card Stayman, so he may think that 3 !d shows a 4-card major").
It is never right to give MI about your agreed methods just in order to avoid giving partner UI.
It is more difficult if W's alert makes E doubtful as to who is right, because "no agreement" (when neither can be sure which version of Stayman they are playing) is alertable.