At most places that serve alcohol anymore there is a "no ID, no drink" policy no matter your age. If you want to have a drink someplace then you as a responsible adult should have the proper ID on you. The establishment has every right to watch to make sure that someone that hasn't been verified is not drinking. They have a lot more than a customer to lose if someone underage is caught: fines and having the liquer license revoked to name a few. Next time make sure you are prepared and don't blame the waiters or other staff for following policies.