S bids 2♦, natural according to the agreements, but alerted by N and explained as transfer. Now S ‘corrects’ this to 3♦. Let’s assume that there was no other indication by S that N made a mistake and that the players don’t play this as forcing. I know, it’s a lot to ask, but these aren’t experienced players.
EW call the TD and claim that S should have passed 2♥, which would end in -2, whereas 3♦ is made. The TD decides that S legally knows, because of the 2♥, that N has forgotten their agreement and therefore allows the 3♦. I wouldn’t, but would you?