I tip for service given not service anticipated.
No way. It makes people lose motivation
It's the golden rule of consumer/vendor motivation - never pay up front.
I have done it the pre-payment way. I learned the hard way that the golden rule is real.
No .. I tip based on performance.
Quite an interesting question..AND did you know that in the old days, the word 'tip' meant 'to improve performance' and the tip was given BEFORE the meal?
I don't know what era it was, but I read that somewhere years ago.
NOT a very good idea today, though!!!!!!!!