1♠ was natural, Acol, 4+ spades
3♣ was natural and intermediate, but alerted because East thought it was Ghestem
X is negative if 3♣ is natural, undiscussed if 3♣ is Ghestem
Before passing South checked the meaning of 3♣ and was told it showed clubs and hearts. At the end of the auction West corrected the misinformation and showed on the convention card that their agreement was to play michaels cue-bids and intermediate jump overcalls. East agreed that he had made a mistake.
The TD ruled that South could retract his final pass if he would have bid differently given a correct explanation, but that if the misinformation affected North's action redress could only be given after play was completed. South declined to change his call.
Result: 3♣X(W)=, NS -470, 0/6 MPs
At the end of play the TD asked North why she had doubled. Had she known the real meaning of 3♣?
"No", she said, "I assumed it was natural, it wasn't alerted". The other three players all agreed it had been alerted.
South would have bid 3♥ or 4♥ had he been given a correct explanation, but didn't change his final pass because he assumed that when North doubled she was aware of its (alerted) meaning, and that North might have a penalty double of clubs.
EW are a strong, semi-regular partnership (who really ought to know what overcalls they are playing). NS are not so strong, but experienced. They have played only one session together, several years ago. South's preferred methods are for double of a two-suited overcall to be a penalty double of at least one of the suits if neither is the suit bid, but takeout of the suit bid if that's one of the two suits shown. He hadn't discussed this with this partner, and while the first part could easily be assumed as standard, the second could not. (He alerted because he wasn't sure without asking that the bid was showing clubs.)
Have NS damaged themselves here, or do you think they're entitled to redress?