[pran]

 RMB1, on 2018-July-26, 07:38, said:

We should not forget that 2NT is only an infraction if they have an agreement to open 2NT on this hand and that agreement is not permitted.

It is nevertheless an infraction if such agreement is not properly disclosed to opponents.

[barmar]

 pescetom, on 2018-July-25, 15:39, said:

Even in Italy, which has a much less creative RA than ACBL, it seems to me that the 2NT opening in question would be an infraction if bid without alert.

How can they be expected to alert it if they have no agreement to bid like this?

[Vampyr]

 barmar, on 2018-July-26, 09:50, said:

How can they be expected to alert it if they have no agreement to bid like this?

If they have an agreement and know it is illegal, surely they will not alert.

I guess the main question is “IS the agreement illegal if properly disclosed?”

If this was answered in the thread, forgive me, it is very late and I cannot sleep in this heat.

[sanst]

There’s another question to be answered: “Are the opponents damaged?” N has nine clear tricks and I don’t see how NS can make another. So, if the 2NT was illegal, and that is a big if, the only thing the TD can do is give a PP.

[StevenG]

 sanst, on 2018-July-27, 02:59, said:

There’s another question to be answered: “Are the opponents damaged?” N has nine clear tricks and I don’t see how NS can make another. So, if the 2NT was illegal, and that is a big if, the only thing the TD can do is give a PP.

That analysis is incorrect. North only has eight tricks. (I'm not sure where you think the ninth is - the diamond is ruffed.) West thinks it's safe to cash out the Ace of clubs for the setting trick because North cannot, by regulation, have a singleton club. Had he exited with a heart, the contract should still be off. So there is damage.

[sanst]

 FelicityR, on 2018-July-25, 10:17, said:

I readily admit I'm no director but if a bid is illegal due to contravening a national association's rules (as opposed to actually making an illegal bid) I would think the best result would be to void any bids that North has made and adjust the score to E/W making 3♦ for 110. Whether that is actually covered in the rules is another matter. The illegality of the bid is on a far higher level than a simple misunderstanding.

The laws define inadmissible calls, like doubling your partner. But here there’s nothing illegal about the call. There can be a regulation in force that an agreement about a call, in this case that 2NT can be made with a (small) sngleton, is not allowed, ‘illegal’ you might call that, but there’s is no evidence presented to that effect. But even if it’s the case, you must consider whether N made the 3♠ call based on UI. If not, and I don’t see that it is, that call is admissible and you can’t decide that itis invalid. You let the play continue and correct the result if the NOS was damaged by a breach of the Laws or regulations or give a PP if you think that that’s warranted.

[pescetom]

 pescetom, on 2018-July-25, 15:39, said:

Even in Italy, which has a much less creative RA than ACBL, it seems to me that the 2NT opening in question would be an infraction if bid without alert.

 barmar, on 2018-July-26, 09:50, said:

How can they be expected to alert it if they have no agreement to bid like this?

We don't yet know if they had an agreement to bid like this, @pran and others have asked but the poster has not addressed the matter.
Obviously if they don't have such an agreement they will not alert, and the opening would thus violate the Italian regulations (which are pretty much the WBF systems policy).

[sanst]

 StevenG, on 2018-July-27, 03:46, said:

That analysis is incorrect. North only has eight tricks. (I'm not sure where you think the ninth is - the diamond is ruffed.) West thinks it's safe to cash out the Ace of clubs for the setting trick because North cannot, by regulation, have a singleton club. Had he exited with a heart, the contract should still be off. So there is damage.

It’s just too hot (37°C) to think properly.