I encourage private messaging or note passing for private conversations.
Most of the time if I'm at a game, I have 4 or 5 different chats going since the DM should be included in any conversation (about the game) anyway, and if needed we can toss up another when someone else is brought into the convo or someone leaves.
Personally I hate meta gaming and you can only bust out SCP-682 ( Anti-Metagaming-Tarrasque) so many times before giving up on some people. And I personally know I struggle internally with meta gaming. If I overhear something critical, I can't just unhear it. And there's no way of knowing if I would have figured something out or behaved in a certain way if I didn't know the thing. So how I act from then on feels unnatural purely because I'm always judging myself "would I do this if I didn't know?"
It's easier to split conversations up so only those who would have been part of it will know
Of course if anyone wants to share the contents of a private conversation, go right ahead. But they have to wait until then.
DM grin widens
DM trying to get you to pass the bottle.
When playing a Lawful character. I declared my character to have exited a room already when stuff happened that would have made my character otherwise want to report the party.
