When West tables his lead face down, East asks North how many aces the 5 clubs answer on Blackwoord promised. The answer was "zero". As playing the "1430" pattern is now nearly ubiquitous in the Netherlands, East asks South if the 5 clubs answer indeed promises zero or four aces, rather than one or four. South confirms that he has promised zero aces.
Lead is a heart, won in dummy. Declarer plays three rounds of trumps, crosses to his hand in hearts, succesfully finesses in diamonds and runs them. Finally the queen of clubs is led from dummy. East, fearing that partner's ace of clubs may now be single, plays low.
Result 5 spades +2.
Of course EW are not amused.
The setting is a pub drive, late in the afternoon, by which time the level of inebriation of the participants tends to be considerable. Both NS and EW play occasionally together. NS do not have a convention card. Under dutch regulation this is enough to rule misinformation.
NS are subaverage, experienced players, EW are very strong players, one of them an international.
South excuses himself profusely, he was just too tired and intimidated to answer correctly. He was not sure what the agreemnt over Blackwood was.
So, how shoulld the TD rule?