No...most mixers have a channel mute on every channel...just have him press the mute on your channel (or channels if you run stereo). If their mixer doesn't have a channel mute, just have him turn your faders all the way off.
Plus if you do original music and you're not famous or you're not playing covers chances are your sound guy is probably getting paid a lot more for the night than you will be (he'll walk out the door with at least $50 to $100 in his pocket while you're fighting the club owner for a couple of drink tickets and a few bucks)...don't be afraid to ask him to do his job.