What is AI?
The bidding goes
1NT - P - P - 2C - P.
At this point the partner of the 2C bidder alerts and explains it as being 23 points plus. (the alert might have happened before the 2nd pass, that was the situation when I was called) From partner's reaction he looks round, sees the opening 1NT bid and then calls me to say that he has given a misexplanation. He then advises opponents (correctly) that it is Landy and I offer the NT bidder the opportunity to change their call given the correct explanation (they could, for instance have wanted to double the 2C call to be lead directing had they held good values).
I let matters rest at that point, but should I? i.e. have the pair start on a strong 2C sequence?
Comments
I'd certainly give his partner a warning for giving UI by his reaction. I might then insist that he respond as he would to an opening 2C bid, presumably with 2D. Obviously, partner then takes that as a 2D response to Landy and replies appropriately.
From there, I'd allow him to "wake up" to the presence of the original 1NT bid, adjusting appropriately if the situation unreasonably works in their favour.
The correct meaning of 2C on this auction is authorised to the player. Nevertheless, the player misunderstood 2C and was prompted to correctly understand 2C by partner's reaction. Partner's reaction is unauthorised information (as per the last words of Law 16B1) and suggests bidding as if the player's original explanation is incorrect. It appears that both players have UI.
Oh I know that - the question is: is the player who was in receipt of the UI from partner's reaction allowed to know it from seeing the 1NT card on the table.
Somehow we have to determine whether not looking at the earlier auction is a logical alternative, and therefore bidding on the basis of the original explanation is a logical alternative.
Even if there is no logical alternative to noticing 1NT and bidding as if 2C is Landy: there can be a breach of Law 72C1, Law 73C1 (see below) which does not mention authorised information or logical alternatives.
Thank you, Robin, 72C is a good one to keep in mind,
Unfortunately I meant 73C :(
What I had in mind is that an honest player who not 'noticed' the 1NT bid and did notice the hitch and then did register the 1NT bid might feel compelled by Law 73C to respond 2D ('waiting') and then to treat 2H/2S by partner as (game) forcing.
But I am worried that this is too much to expect from an average player and not something a director in a club should insist on.
72C is applicable here, too, though. While it's not an offence, per se, to give UI to partner, it is an irregularity to give partner information by extraneous remarks or gestures. The player could be expected to realise that such an irregularity could damage the non-offending side.
I think the player who didn't initially notice the 1NT bid can be expected to notice it at some point and then realise with AI that the explanation is incorrect. The question is when, after partner's intrusion, he's allowed to notice and act on it without further irregularity.