Usually, the issue is either: "waited until it was good to take it" blocking the suit or transportation, or "suit (usually trumps) breaks X-Y, need to find a different line of play" that doesn't work as well The first one is obvious; usually, declarer will make it *very clear* if the second applies. In fact, she'll be complaining about it *before* you even get to the point where you mention the trick transfer. I disagree with "put the NOS up to the challenge" in general because once the hand's over, it's *over*, and getting back into that mindset is hard, and leads to misplays that they absolutely wouldn't have made at the table. Anybody who's tried to do a bidding poll knows this; anyone who has attempted to lead an offender to their comparative call, especially in the auction 1m-(1♠)-1♥, knows this. Whether we should put the offenders into that trap, it's unfair to punish the NOS that way, even if the director sees a line obvious to him that the Flight C declarer would "never find". This feels like "how dare you give me, a Flight A player, a worse score than *that player* would ever find at the table, just because I did something wrong?" Not saying that Axman would ever say that; he really does want to ensure a fair result. But others *do*, and definitely would prefer if the Laws were the way axman wants (partly because the C players, confused enough with the whole TD thing, would misplay; partly because after the hand, especially knowing in advance that they will be asked, the stronger player definitely *would* find the "obvious" double-dummy line, and also the reasoning why it is obvious). I'm not saying double-dummy; neither do the laws. I'm saying "the Director deems that the non-offending side is insufficiently compensated" (64C1). My comment on "it's rare, but it matters" about the *second and subsequent* revokes is 64C2a, by the way.