Posted 2017-May-10, 11:57
So this is my issue ("But everybody does this").
As usual, it's probably right to expand the acronym. The actual Lawful quote is "but he need not disclose inferences drawn from his knowledge and experience of matters generally known to bridge players." Sure, we refer to it as "general bridge knowledge" from antiquity, but that's the quote.
To my mind, it is GBK that AJ9xx is worth more, on average, than KQ tight, and that AJ9xx and a couple of aces could easily be worth more than KQ KQ AJxx. It is GBK that "if it looks like 15 balanced, people will open it 15 balanced". Would people look at your hand as dummy and say "that looks like 15 balanced?" Even though there are odd 16s that are worse than this 13? Would not treating that hand as a 15 count be a Logical Alternative (given that we don't poll straight Walruses)? If so, it's probably GBK that this hand will get upgraded. But I bet it's not. I bet it's something not drawn from experience "generally known to bridge players", but from experience "in the partnership" - and as evidence, I show the fact that having to ask this question - "what do you upgrade?" *is* in fact GBK - at least in Flight A (in flight C, they Walrus. Trust me, they Walrus. Most of the time, the Flight A players "get away with" their upgrades without question because the hand doesn't come down, and they also don't count the points!)
Upgrades of more than half a point (into NT - you'll get more leeway with "shape rules") are not normal - and hiding that is CPU, not GBK. Even if it were, a player "need not" disclose - that doesn't mean they "must not" disclose. It's intended to be a backstop to deal with people who don't realize that an opener opposite an opener, with a fit, is game, even if it's not 26 high (but not, for instance, that "since we open all 10s and many 9s, our 'limit raises' are 11-13, not good 9-12" - the "since" clause isn't necessarily known or remembered, and we tend not to require the opponents to work out the inferences from the opponents' unusual parts to their system), or that balancing against 1H-2H;p might not have full values.
IT IS NOT INTENDED to be a shield to hide knowledge gleaned from this particular partnership, or the knowledge you have of "general flight A tendencies in your area", or "we have no agreement, but I've seen him pass a bunch of nondescript 13s, 14s with his regular partner and come in again like this". I don't care how you upgrade (or use Ogust, or preempt, or whatever). I do care if you don't feel like explaining it to the opponents. I really care if you hide behind GBK, *knowing that* your partner will be less in the dark than the opponents. I care to the point of C&E, if that's *why* you hide behind GBK.
But, of course, nobody here - especially Nick - would do that.
When I go to sea, don't fear for me, Fear For The Storm -- Birdie and the Swansong (tSCoSI)