The Bahamas Atlantis Resort has it figured out. They charge you a fixed 15% gratuity you cannot avoid, and you can tip on top of that. This way a breakfast ham/egg croissant + jerk chicken sandwich + 2 coffees will set you back $45.
I found that in Miami they add 18% by default in the check. When I was there earlier this year, I did not realize it the first day and ended up paying 20% tip on top of that.