NS play Acol with four-card majors, 12-14 NT. 2NT was Jacoby (GF, 4+♥), 3♠ was a splinter (both alerted). Cue-bids are normally first-round controls. North responded 5♥ (two key cards without ♥Q), said "no, sorry" and replaced it with 5♠ (two with). The director was called, this was judged to be an unlawful deliberate change of call and 5♥ was reinstated, South warned about unauthorized information from the attempted change.
South argued that his hand was too good in the context of the auction so far to make pass a logical alternative.
Do you agree?