Why Won't McDonald's Give My Kid A Cup Of Water With Her Happy Meal? - The Consumerist: "Whenever I've tried suggesting a water with the meal, the cashier just flatly replies that they can't do this, because the order for a Happy Meal requires milk, chocolate milk, a fountain drink, or a juice box. When I asked if I could choose a soda and have them fill it with water instead (not asking for a discount, mind you, just asking for some water), they charged me for a medium soda...
When I called to complain to the manager, he immediately said the same thing, and then when I pointed out that I wasn't asking for a discount or something extra, that I simply wanted the cup filled with water instead of soda, he saw my point. I asked him to educate his cashiers, but sadly, I don't think that's going to work."