Posted 2019-November-22, 10:50
In essence you are half correct: the TD has ascertained that the explanation was correct (although there is a presumption that the explanation is wrong) - so presumably he looked at convention cards or asked the players away from the table as to their actual agreements.
There is some doubt whether North has now picked up that South has mis-bid. If South is known to mis-bid a lot then this fact should be declared to the opponents and failure to do so is an infraction (misinformation) . The EBU has the following guidelines - white book 1.4.1 (in part)
"Players are required to disclose their agreements, both explicit and implicit. If a player believes, from partnership experience, that partner may have deviated from the system this must be disclosed to the opponents. If a player properly discloses this possibility, the player will not be penalised for fielding it, although there may be a penalty for playing an illegal method."
(FWIW in the EBU a 2NT bid showing either 5-5 in the minors or a strong hand is a perfectly legal convention (I play a variation of it myself))
1.4.2.6 has this
"A partnership’s actions following a misbid may provide evidence of a partnership understanding which should have been properly disclosed. Unlike psyches, misbids are not classified as red, amber or green, but can be recorded.Because of the difference between the player’s understanding of their call and any alerts and answers to questions by their partner it is quite common for unauthorised information problems to be present."
So if South has no record of mis-bidding, North is fully entitled to assume that he has as there is no implicit agreement. He might, in the interest of full disclosure, tell opponents that it sounds from the double that South has mis-bid (not that that will be of any great comfort to West, of course).
What would be harder to explain would be if a double is actually for takeout (in the minors) - there is probably no partnership agreement on this - but what would South do if holding
-
X
KJTXXX
KJTXXX
for instance? (maybe bid 4NT? Some pairs will differentiate between a double and 4NT depending on the strength of the 2NT bid)
Note that even if South might have misbid and North has known this, West is not entitled to know whether a misbid has occurred. In effect he is only allowed to know "Shows 5-5 in the minors although we have played this as 20-21 balanced and South may have forgotton the change" or WTTE (This explanation is of course UI to South).
As Terence reese said - "a convention is an agreement between partners, not an undertaking to opponents"
In Summary.
1) North is not compelled to bid as though his explanation is correct.
2) If he has no reason to expect South has misbid then that is the end of the matter.
3) If he knows South has a tendency to misbid conventions (especially this one!) then he must declare it.
No matter how well you know the laws, there is always something that you'll forget. That is why we have a book.
Get the facts. No matter what people say, get the facts from both sides BEFORE you make a ruling or leave the table.
Remember - just because a TD is called for one possible infraction, it does not mean that there are no others.
In a judgement case - always refer to other TDs and discuss the situation until they agree your decision is correct.
The hardest rulings are inevitably as a result of failure of being called at the correct time. ALWAYS penalize both sides if this happens.