Unless you sipped all the drinks on the tray, how can you say the bar waiter tried to sell alcohol to a minor? Some of the drinks on the tray are always virgins. Sometimes they are all virgin and the waiter has a glass of rum so he/she can add liquor if the customer wants a regular drink.
Over the past few years Carnival has impressed me with their rigidity regarding the drinking age. The staff can be immediately terminated if they sell to a minor.