cherdano, on 2013-March-22, 05:33, said:
I can't remember a clearer case of UI suggesting a particular action (passing 2S, in the hope that we are in a 4-3 fit, and survive).
Seems that there are several levels to this decision.
The first level, which is what the AC seems to have considered, is that the 2
♠ bid doesn't show a real suit -- all it shows is that partner's spades are better than his hearts. For all you know, you're in a 3-3 fit (probably not worse, though -- the 1NT overcall and your diamond length makes a freaky distribution unlikely), probably not your best suit. Playing here instead of trying to get back to your likely 8-card fit in diamonds is not taking advantage of the UI.
The second level, which is mentioned here, is that trying to recover could cause the wheels to come off even further, propelling you way too high. The AC didn't consider this. I think they suspected that partner might figure out that this is what you're doing, so your recovery attempt could succeed.
gnasher wrote "Matchpoints. Systemically 2♦ showed both majors, but South forgot and intended it as natural. At this point South passed 2♠. The appeal was mainly about the later auction, but the appeals committee commented "South ... passed 2♠ when the UI had suggested otherwise." Do you agree? We can assume that 1♦ and 1NT were standard for North America. 2♦ was alerted and explained as both majors."
I agree with Cherdano that the UI suggests passing and the committee are mistaken. Especially as, absent the UI, 2♠ is likely to be shapely and constructive (if not forcing). Well spotted Gnasher!