Teams: lead 7♥; Table Result 7NT=
SB was quick to call the director on this hand when ChCh stumbled into a makable grand. West led the seven of hearts, but ChCh won with the ace, ran the queen of spades, covered by the king and ace, ran the nine of spades and cashed two more spades, triple-squeezing East with any discard costing two tricks in that suit. So 7NT came in.
"DIRECTOOOOOOOOOOOOOOOOOOOOR" typed SB, West. "There was a breach of 40A4", which he quoted from memory:
"4. The agreed meaning of a call or play shall not alter by reference to the member of the partnership by whom it is made (this requirement does not restrict style and judgement, only method)."
"RR was playing standard methods and South was playing Precision". "The fact that North would have made a 2D relay in Precision is neither here nor there. He clearly played his partner for 23-24 and bid 7NT on that basis. So North was playing Acol or similar, South Precision. That is an illegal method and we get 3 IMPs I think."
OO was unsure. "Let me consult," he said, "it may just be rub of the rabbit".
How do you rule?