[mycroft]

yes, I hadn't got that far, either. Oops. On the other hand, I don't think that you can bid 2NT "invitational with a diamond stop" with a hand that would have bid 1NT that wasn't "invitational with a diamond stop" *and* get to use the 1NT as AI. I argue that, because

L27B1a explicitly says "Law 16 does not apply", but
L27B1b says the "auction proceeds without further rectification", with no mention of Law 16
before in both cases sending you to L27D.

But I can see an argument going the other way.

In any case, if "the only way to get to 2NT with these hands is to make an insufficient bid", then no matter what L27B1 path gets you there, it's to be disallowed, though. If the resulting contract, however, "could [not] well have been different", then things get to work. (obviously, if we end up taking L27B2, and "the only way...", then we go via Law 23, not L27D, as L27B2 says to do).

Having said that, club TDs are club TDs, and I wince whenever I get a "less Lawful" ruling from them - especially if it's to my benefit. I also - at different times, of course, *not* at the table - attempt education, especially about these weirdies (well, one level down; the normal ones, not the corner cases that get this forum into so much trouble). But in the end it isn't the BB, and the better TDs are at the BB to give the more Lawful rulings.

As far as "how to correct this", I don't mind "IB = partner barred" - it's a bit draconian, but I wouldn't mind a few laws being more draconian, myself; but I don't like "IB = partner barred unless you do one thing, but partner has to treat that as what it would have meant as well", as I've said before. I think that that law is equivalent to "if you're really lucky, partner isn't barred. But if you're not, you're more screwed than when it happens to your opponents next time." I think L27D is a reasonable compromise, in fact, if the TD reads it and applies it. If the argument for marking a Law as bad is "if the TDs don't follow all the Law then it's bad", then that's an education problem, not a Law problem. If the argument is "the education to get TDs to do it right is too hard", that's reasonable.