HighLow21, on 2012-February-01, 16:04, said:
I'm not clear on the rules... but if partner forgets the meaning of my bid, and as a result ends up in the wrong contract and goes down, how exactly is the opposition damaged? I'm not clear on the ruling when partner forgets the meaning of a conventional bid. I do agree that E/W can do better than +100.
Also, I think E/W can make 11 tricks in diamonds, double-dummy, not merely 9. A heart lead can jeopardize that but is unlikely. The real loss is the value of bidding and making the 11-trick vulnerable game, not simply +110 vs. +100.
If there is MI then any adjustment is based on the possibility of the opponents' calls being different.
HighLow21, on 2012-February-01, 16:21, said:
That seems reasonable. This is a ruling issue much more than an analytic issue. To me, if the ruling is that they were damaged, they should get +600 for 5♦=.
The norm for adjustments is a weighted score. Your ruling is only right if you are sure or very nearly that without the MI, all reasonable bidding sequences reach 5
♦ and declarer is always or nearly always likely to make 11 tricks.
I really do not believe that this is anything like the case.
Incidentally, if my partner bids a major in which I have a singleton, I feel more likely to want to bid an AKJTxx suit if the opponents seem on their way to 3NT than if they seem on their way to a part score, where I shall have a second chance anyway. So I think 3
♦ is
more likely not less over a natural 2NT so I see no damage.