Posted 2015-July-30, 09:32
See Frances' comment - they have *no way* to turn off the "has support" information. Neither do I, nor "anyone" in my area (but we play this raise slightly stronger, usually limit+). So what happens if partner has the hand that "can control the auction", fails, ends up in 4 of their "fit", and I take the sacrifice, only to find it's a phantom because partner has 4 of them rather than the 2 I can count?
Hard for "everybody" to know this when it's not explained, and there is no experience of it being anything else.
Having said that, if "good single raise" is the *agreement*, and partner decided to deviate because he could "control the auction", and it's a surprise to overcaller, that's legal. If it's not a surprise to overcaller (even because they've read the same books), then we might rule MI.
I have to admit I always got caught by my 1♦ in Precision. "11-15, 2+♦, 1NT would be 10-12"; on the 1NT rebid, "oops, could be a average or worse balanced 16. I always forget that in my explanation". Yes, that could have caused me problems; no, it never did.
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