To get straight to the point, the /mute command should be more effective.
Currently if you /mute ID or name, when the user changes teams or leave/re-enters they are unmuted again.
Maybe it should be fixed so it'll keep people with that name and ID muted, only if they're in the server that you muted it in. (Mute ID 3 in one server, leave and go to another server and ID 3 is NOT muted there. Once you go back to the original server ID 3 is still muted, same with names.)
It gets very annoying when people spam servers, get muted by players and just rejoin and continue, so this would prevent things like that.