No. But I've tipped them (both bike and motorcycle) when they've done work off the clock for me.
For example, I was installing a new SRAM crank and I didn't have the right tool to torque the bottom bracket. Carried the frame in with the BB screwed hand tight and the guy torqued it quickly for me - he wasn't going to charge me for that two minutes of time, so I slipped him a $10.
KeS