Are you saying that you've already pre-paid the "services rendered" part for the driving, grocery stop, etc. as well as pre-paid the "tip"?? The driving part I can understand, but ummm, what's the incentive for driver to go "above & beyond" so to speak when he's already been paid for basically doing nada? Is it a huge group you're travelling with? I don't understand why you have to prepay a tip - a tip is well, a tip - supposed to be a bonus for doing a good job. I was going to try them our next trip, but if I have to pre-pay a tip, I'm just not cool w/that.