Lead ♦2; Matchpoints; NS+1370.
"I think we would have defeated the last hand if you had cashed your ace of trumps before I revoked," said South, the club's equivalent of the Rueful Rabbit, at a local club recently. "Play this one, please," said North, and South bid "Stop, 2NT", alerted by his partner. That alert came as a surprise to South, who had not seen the 1♥ bid. Over his partner's 3D, he thought he was supposed to select his LAs using 16B, with no 75A to worry about this time, as he had not forgotten the system, but had just overlooked the opening bid.
He therefore tried 3NT - he had a heart stop after all, and was surprised again when his partner jumped to 6D. Still he must have long diamonds and RR had AKx of those so he put the dummy down. He had long perceived the advantage of being dummy, and indeed North had no trouble with the play, picking up both black queens which were marked from the opening bid. He could not even misguess trumps, as East did not have ♦JTx.
East, a chap who looks like SB, was unhappy. He thought South had taken advantage of the UI which told him that he had not seen the opening bid, and he had an obligation to continue not to see it, and to bid 3H. That might have led to a different contract, perhaps 5D+1 by North which would have been a bottom. How do you rule?