[pretender]

South deals NV vs Vul

1♠ (X) 2♠ (3♥)
3♠ (3♥!!)

West's insufficient 3♥ gets accepted by North who passes. Is East allowed to just bid 4♥ (on the belief that pard wanted to bid a vulnerable game)? What's AI/UI here?

[pran]

pretender, on 2014-May-08, 09:27, said:

South deals NV vs Vul

1♠ (X) 2♠ (3♥)
3♠ (3♥!!)

West's insufficient 3♥ gets accepted by North who passes. Is East allowed to just bid 4♥ (on the belief that pard wanted to bid a vulnerable game)? What's AI/UI here?

So far there is no UI in this auction.

[barmar]

Agree with pran. If an IB is not accepted, then it's withdrawn and becomes UI to his partner. But when it's accepted, the auction proceeds normally. The IB is AI to everyone.

There can still be an adjustment if the IB leads to a good result that couldn't have been achieved without it, and the TD judges that South could well have known that it would work to his advantage.

[gordontd]

pretender, on 2014-May-08, 09:27, said:

Is East allowed to just bid 4♥ (on the belief that pard wanted to bid a vulnerable game)?

Why would he believe that when his partner was trying not to bid game?

[pretender]

Let's add some more details and see if that changes things. This will also answer gordontd's question.

What if:

The infraction is pointed out by N/S or discovered by W himself before N bids, and
W says, "oh, I meant to bid 4♥" or "let me just correct that to 4♥"

N still has the option on the infraction, and now chooses to pass. Any difference?

[pran]

pretender, on 2014-May-08, 10:39, said:

Let's add some more details and see if that changes things. This will also answer gordontd's question.

What if:

The infraction is pointed out by N/S or discovered by W himself before N bids, and
W says, "oh, I meant to bid 4♥" or "let me just correct that to 4♥"

N still has the option on the infraction, and now chooses to pass. Any difference?

No.
If North accepts the IB then there is no UI.

However, as Barmar pointed out: If the situation leads to a favourable contract EW and this contract could not reasonably well have been reached without the irregularity (the IB), then (and only then) there is a case for TD to adjust the score.

Note that if West without pause for thought at the time he realises that he has made an insufficient bid somehow utters that he really intended to make a different call (e.g. 4♥) we most likely have a Law 25A case and not a Law 27 case.

[mycroft]

1) any statement made over and above the call made is UI. But straight up, with no "action", partner gets to guess whether they meant to bid game, or meant to compete as high as necessary, or meant to compete to 3♥. No UI; possible CPU if there's experience on when partner makes these IBs.
2) I think Barry and Sven are referencing L27D with the "if the IB gets them to a contract they couldn't get to" - but that's only if the IB is not accepted. The idea being that L16 (with the full LA restrictions) doesn't apply, because it's too much of a restriction to say "you have to bid X or partner must pass, but partner has to bid as if you *meant to bid* X - which might not even be reasonable"; so what it says is "you have to bid X or partner must pass. Partner can bid as if you showed (what she thinks the IB would have meant), you don't have to hang yourself, but if that gets you to a contract you couldn't have got to without infraction, we'll adjust".

I don't think that applies, however, if you accept the IB ("If following the application of B1 above").
3) Yes, if it's possible to prove despite 1) above that the IBer did a slip-of-the-fingers, we are in L25A, not L27, and then the only "UI" is "partner actually pulled the 3♥ call when he meant to pull 4♥" - which is no I at all to manage.

So I guess I'm sort of disagreeing with everybody.

[gordontd]

pran, on 2014-May-08, 14:04, said:

No.
If North accepts the IB then there is no UI.

This is quite wrong. Any comment to the effect of what West intended is UI, and in this case suggests bidding on rather than passing. Without seeing East's hand we can't tell whether Pass was a logical alternative to bidding 4♥

[blackshoe]

gordontd, on 2014-May-08, 15:15, said:

This is quite wrong. Any comment to the effect of what West intended is UI, and in this case suggests bidding on rather than passing. Without seeing East's hand we can't tell whether Pass was a logical alternative to bidding 4♥

Well, actually, any comment related to the bidding is extraneous. There may be implications from such a comment; it is those implications that are UI.

[pran]

mycroft, on 2014-May-08, 15:02, said:

[...]
2) I think Barry and Sven are referencing L27D with the "if the IB gets them to a contract they couldn't get to" - but that's only if the IB is not accepted.
[...]

Correct, I was too quick.

[gordontd]

blackshoe, on 2014-May-08, 15:37, said:

There may be implications from such a comment;

There are implications from this comment.

[blackshoe]

gordontd, on 2014-May-09, 00:50, said:

There are implications from this comment.

Of course. I was making a more general statement.

[jhenrikj]

barmar, on 2014-May-08, 09:46, said:

Agree with pran. If an IB is not accepted, then it's withdrawn and becomes UI to his partner. But when it's accepted, the auction proceeds normally. The IB is AI to everyone.

Not entirely correct. If an IB is not accepted, but an 27B1(a) correction is possible, then law 16D does not apply to the withdrawn bid. The classic example is this...

1♦ - (2♣) - 1NT...corrected to 2NT according to 27B1(a)

1NT shows 6-10, 2NT in this situation is 11-12, the opener has no obligation to bid 3NT with 15 hcp since the information that his partner tried to bid 1NT is AI. But of course 27D applies if there is no other way to end up in 2NT.

[mycroft]

I use as the "classic" example 1♣-(2♦)-1M. Opener does not have to assume 5M, or 10+HCP; and there would usually be a different way to show this hand that would get them to whatever contract they're going to get to.

[Zelandakh]

pretender, on 2014-May-08, 10:39, said:

The infraction is pointed out by N/S or discovered by W himself before N bids, and
W says, "oh, I meant to bid 4♥" or "let me just correct that to 4♥"

These seem to be two separate cases despite sounding similar. In the first case it sounds like West has mispulled and we are potentially in unintended bid territory. In the second case East still does not know whether West is simply making the bid sufficient having meant to raise to 3♥ (having assumed a pass from South) or meant to bid game all along, although the former is perhaps more likely.

So now we have 3 cases - as described in the OP without comment and the two described above. Do you want all three to be addressed or only a specific situation?