Legal Question in Civil Litigation in California

I'm not sure what you mean by a "discovery meeting." If you're talking about a deposition, it's an unresolved issue as to whether outsiders might attend. If they have no connection with the case -- and especially it's a crowd -- it might be appropriate to stop the deposition (before it even starts) after stating on the record what the problem is. Then, a party would seek a protective order from the court explaining why those interlopers should be excluded.