[han]

gnasher, on 2012-July-26, 08:51, said:

I don't think there's any obligation to tell the opponents that you think you have UI, as long as you follow the rules about what to do about it.

On the other hand, last weekend (in a very non-national Swiss) this occurred:
EW bid to a making slam without NS noticing anything odd. At one point West signed off in game and East moved. At the end of the auction, East volunteered the information that he thought his partner had hesitated before signing off, but he was confident that he had acted properly. NS told the director that they hadn't noticed any hesitation, but if there was one they didn't think East was allowed to bid with his actual hand. The director agreed and adjusted the score. So justice was done, but only because East had told the opponents about the UI.

Your east thought he had acted properly, but still the score was changed afterwards.

This was the situation at our table:

---

I was north and when I bid 2D I thought it showed a strong raise like an inverted minor. It didn't, and when it was not alerted I realized what our agreement was. So, I had UI. I figured that if my partner made any invitation to game or slam, I should not accept it, since for a strong raise I did not have extras. However, when my partner forced to game and then investigated slam, I also had no reason not to bid what I had in my hand: clubs, a club cue, a spade cue and two keycards.

As you can see, slam was good but went off after the heart lead when spades broke 6-2. I doubt the opponents would have been interested in hearing about my UI if the slam would have made, but I guess it is proper to tell them about it and let them decide.

[pigpenz]

looks like even bidding 4♣ would have helped if were trying to get to grand

4♣ 4♥
5♦ then only a guess