DozyDom, on 2019-November-13, 20:27, said:
N has given UI; that is nowhere near the levels of unethical behaviour needed to merit a procedural penalty, and it doesn't impact the S hand's decision, so I'd think that the result stands.
I disagree. Law 20F5 says "(a) A player whose partner has given a mistaken explanation may not correct the error during the auction, nor may he indicate in any manner that a mistake has been made. ‘Mistaken explanation’ here includes failure to alert or announce as regulations require or an alert (or an announcement) that regulations do not require.
(b) The player must call the Director and inform his opponents that, in his opinion, his partner’s explanation was erroneous (see Law 75B) but only at his first legal opportunity, which is:
(i) for a defender, at the end of the play. (ii) for declarer or dummy, after the final pass of the auction.
North has committed an offense that the laws call "a serious matter indeed". This is well beyond something that "will incur a penalty more often than not". See the Introduction to the laws.
I am aware that many, if not most, directors will ignore this part of the law because, to them, giving any procedural penalty at all is anathema. But IMO that's not the way to rule the game.
NB: an action does not have to be unethical to rate a procedural penalty.