I would ask, if you really want one...most places we asked the answer was yes. No refills on the milkshakes, though. And not on kids dining plan, only for adults. Now the Plaza might be one that says no for your beverage, since milkshakes are a dessert there (all ice cream based desserts) However, since you're getting an app (typically soup or salad at The Plaza) & entree (we had hot sandwiches & french fries) you may not be wanting a dessert at the end anyway...in which case if you want a milkshake as your drink, then you might want to order the milkshake as your dessert & ask for it to be served with your food.