BudH, on 2017-October-25, 19:49, said:
"if the insufficient bid is corrected by the lowest sufficient bid which specifies the same denomination(s) as that specified by the withdrawn call, the auction proceeds without further rectification...." Laws 26B and 16C do not apply but see D following.
" if the insufficient bid is corrected with a comparable call, the auction proceeds without further rectification...."
I never thought the principles used here were that difficult to understand. Perhaps I'm mistaken!
I've not found the principles difficult, although I sometimes struggle to decide what possible meanings can be attributed to a withdrawn call, and (lately) under what circumstances the director can award an adjusted score after a sequence featuring a withdrawn call has worked out well for the offenders.
BudH, on 2017-October-25, 19:49, said:
Assume a different auction (3♠)-2NT where 2NT is not accepted by LHO. The Director learns the 2NT bid was intended to show both minors over a 1♠ opening bid. So what is the lowest sufficient bid specifying the same denominations? In this case it is 4NT, assuming it also shows the minors, and assuming 3NT is natural and not showing the minors.
How would the director learn that the intention was to show the minors? He's not going to ask. He may of course decide that "showing the minors" is an attributable meaning for 2NT.
BudH, on 2017-October-25, 19:49, said:
So the Director likely does need to know what the offender's thought process happened to be causing the insufficient bid. Also, this is probably a good reason why the Director should see offender's hand to check this reason is valid (although many think the Director should rarely consult a hand or hand record when at the table).
I agree that the director does not need to know offender's thought processes, as the possible meanings of an insufficient bid are those an outsider could attribute to it. The director may need to take the offender away to ask about their methods, as it may not occur to them that the offending partnership play certain conventions (e.g. transfers) in unusual situations.
I don't think it's ever a good idea for a TD to look at offender's hand in a live auction. If offender wants to choose a replacement call that doesn't show the cards they hold, they are free to do so, and the TD should not try to stop them. If the offending side get a good score as a result, the TD may need to have another look and possibly adjust the score, but I'm not the best person to ask about that at the moment.