IMPs; Lead K♥; table result +1430
Our 'friend' from a North London club, who looks and behaves like SB, was involved in another dispute recently, after a quiet few months. South was known to be a sharp operator, quick to exploit the foibles of weak players. West led the king of hearts against this poor slam, reached because North thought 3C showed a non-minimum, and South thought it showed a minimum. South won the heart lead and led the ten of diamonds, covered (perhaps wrongly) and won with the king. Declarer now cashed the ace of diamonds and called for a "small diamond" from dummy. When, East, not the sharpest pencil in the box, discarded, the hand was over. SB, West, called the TD and argued that the expression "small diamond" was a breach of 46A, and declarer "could have been aware" that the infraction would benefit his side, increasing the chance of East going wrong, as it could have given East the idea that the "small diamond" was not a winner.
How do you rule?