I just noticed...
Law 21B1a allows a call to be withdrawn and replaced without penalty after MI discovered, providing that call was influenced by the MI.
But the play equivalent:
Law 47E allows a Card to be withdrawn after replaced without penalty after MI discovered
Has no requirement to show the play was influenced by the MI.
I wonder why the difference - any ideas?
Comments
The Law 47E2a correction has a fairly narrow window – only if a player discovers misinformation after playing their card to a trick, but before the next card is played. This implies that the correction must have been given during the play.
It's quite rare for explanations to occur at all during play – pretty much the only time is as a reply to a question by an opponent (usually by declarer). Generally speaking, if the answer weren't relevant to declarer's play, declarer wouldn't have asked. So if Law 47E2a ever triggers, it's very likely that the previous play would have been influenced by the misinformation.
(The Law in question is one that's likely to only rarely come up; I don't think I've ever seen a Law 47E2a correction. The most likely scenario I can imagine in which it would be relevant would be if declarer asks a question, a defender answers, and then declarer immediately plays a card while, but before, the other defender tries to correct the misinformation.)
Writing this answer lead me to notice a similar anomaly – if a player gives a misexplanation during the play, could/should their partner correct it? Law 75B3 says "while the auction continues", so it presumably doesn't apply if the answer is given during the play. It seems unclear to me from the present Laws whether a defender should correct a misexplanation given by the other defender, whether declarer should correct a misexplanation given by dummy, and/or whether dummy should correct a misexplanation given by declarer. I can see some argument that misinformation given during the play need not be corrected at all, because I can't see any Law which requires the misexplainer's partner to speak up…
It can arise on opening lead when the lead has been made face-up and is therefore not entitled to a L47A withdrawal.