[charliejef]

You are playing in a very casual game in the Acol room with a new partner from the lobby.No system card has been agreed.On our second board,pard opens 1NT,doubled on my right.I bid 2D and put a “ chat” to the table “ still a transfer.” I receive a private chat from my left ,” under the rules you’re not allowed tell your partner your bidding system.” I responded to the table that I was fully familiar with the rules but as this was only our second hand together I would expect some licence.
Ok,in a more serious game,I would ask the oppos if they were happy for me to tell pard.But in this instance the opponents were advanced players and I expected that there would not be an issue.The response to my comment was that he ( left hand opponent )would be leaving at the end of the hand.
Is there any acceptable etiquette in situations like this?

[jillybean]

I agree, we want to play bridge, not poker.

[Huibertus]

charliejef, on 2025-November-29, 15:45, said:

You are playing in a very casual game in the Acol room with a new partner from the lobby.No system card has been agreed.On our second board,pard opens 1NT,doubled on my right.I bid 2D and put a “ chat” to the table “ still a transfer.” I receive a private chat from my left ,” under the rules you’re not allowed tell your partner your bidding system.” I responded to the table that I was fully familiar with the rules but as this was only our second hand together I would expect some licence.
Ok,in a more serious game,I would ask the oppos if they were happy for me to tell pard.But in this instance the opponents were advanced players and I expected that there would not be an issue.The response to my comment was that he ( left hand opponent )would be leaving at the end of the hand.
Is there any acceptable etiquette in situations like this?

It's simply illegal according to the Bridge laws. If you get leniency you are playing a game according to a different rules set, it no longer is called bridge. If you want to play bridge take a few minutes before the game starts to agree on basic things like "system on" after 1NT gets doubled.

[smerriman]

Huibertus, on 2025-November-30, 02:43, said:

If you want to play bridge take a few minutes before the game starts to agree on basic things like "system on" after 1NT gets doubled.

If that's your definition of bridge, I doubt you'll find a single hand of bridge played in the BBO casual rooms. 30 seconds of discussion is likely enough time for you to get booted for being too slow.