"KINDLY SHUT UP - THE AUDIENCE DIDN'T PAY TO LISTEN TO YOU!"

To Guest Ed. Sorry you didn't realise this was meant to convey the essence of the message and would never have been used. That's why I am seeking some witty slogan/message to convey the same thing.

The event is in a private function room but it relies on volunteer unpaid bar staff, some of whom believe that it is acceptable to talk through a performance if you don't like it.