In outside of North America you tip in advance for service. Some places in the US/Canada are beginning to catch on*

If you don't tip before your meal or stay in someplace you don't get to eat or stay at all. I was charged 25% tip for my stay at a $250 a night hotel in Paris and all it had been was a room with a single bed smaller than a twin and a tv.

*gratuities are becoming more common - especially in the food service industry. Check your bill before you tip! You may have been charged one already.