I agree with everyone above, in theory. I used to work in a restaurant, so I know how much the wait staff depends on tips. However, in real life (from my observations on past cruises), I can tell you most people who went with alternative dining options did not tip the dining room wait staff. I don't agree with it, but that's the reality. We often had table mates who never showed up for meals, and they don't show on the last night of the cruise (the customary time to hand out tips).