[123ekim]

we are playing 2/1 in a sanctioned ACBL tournament
North bids 1 spade-- South bids 2 hrts--North bids 3 dmds-- South bids 3 spades--North bids 4 hrts (opps ask and are told that it is a cue bid)--South bids 4NT--North responds 5 clubs ( opps ask what does that mean and South states that it is a 1430 response showing 1 or 4 controls in SPADES)-- South bids 5 spades.

North originally thought he should be responding in hrts so now he corrects his mistake by bidding 6 spades ( he has the AKQ of spades and no other aces)

1. Did South make a mistake in fully describing his partner's bid?
2. North certainly took advantage of his mistake based upon South's explanation. Do the opponents have any recourse

[blackshoe]

Was this online, so that North did not "hear" his partner explain 4♥ as a cue bid? If he didn't hear that, presumably he didn't hear the explanation of 5♣ either. If he heard both, then he wasn't paying attention to the first explanation, which is not too smart. IAC, if he heard the explanations, they are UI to him. Could someone show that this UI suggests bidding 6♠? Quite possibly. If so, then if 6♠ makes, then EW were clearly damaged by illegal use of UI, and the score should probably be adjusted to 5♠+1 for both sides, though I'd want to see all four hands to be sure. That's the answer to your second question. The answer to your first depends on what NS's actual agreement is.