IMPS Lead A♥ Table Result E/W -800
East seemed a bit miffed with their opponents' approach to the game on this hand at a local club. NS had agreed to interchange 4C and 4H (and 4C and 4S over 1S-(dble)) because the EBU regulations did not require either to be alerted. They also interchanged 1M - X - 3M with 1M - X - 2NT (this time alerting the latter correctly) because opponents never asked.
The NS convention card was complete in all details, and the TD was forced to rule no infraction. 1H - X - 4C would have been a general pre-emptive raise to 4H. NS argued that OB5E4 was quite clear, and although they accepted that 4H had a potentially unexpected meaning, they would have been wrong to alert it. They also argued that the bad result was mainly unlucky, although West's takeout double was to blame, and East would have had an awkward bid if 4H was just pre-emptive. Do you agree with NS?

Help

