The auction:
1♣ is alerted but not asked (the 2+ meaning is clear to the opponents, it's the only alertable meaning of 1♣ at the club other than 1 pair that plays strong club)
1♥ is alerted but not asked (again, Transfer Walsh is common at our club)
1♠ is alerted but not asked
NS are familiar with Transfer Walsh. About 35-40% of the field plays it.
Before the play, West asks North what the double means. North says: "The other two suits". West understands this as hearts and diamonds. South has, however, spades and diamonds and West goes down in a contract he could (would) have made if he had known that South had the spades.
West is surprised about the layout and asks South whether the explanation was correct. South replies: "Yes, I showed the other suits and I had the other suits." It becomes clear that North knew all along that South had spades and diamonds.
North claims that the error was with West for assuming that "the other two suits" meant "the red suits". West shouldn't assume. He can ask a follow up question. The TD has explained NS that you can hardly ask from West that he asks a follow up question if he thinks that he has understood the explanation and that -in the context of a transfer- the logical meaning of "the other two suits" is "hearts and diamonds".
The TD rules that "the other two suits" is misinformation. West was entitled to understand it as the red suits. He rules 2♠ made and additionally gives a 2 IMP penalty to NS for the MI. (This was the third MI case against NS this evening and NS have been lectured before on their "methods for disclosure".)
NS appeal. What do you decide?
Rik