I went to through that 3 months ago, and asked the bar tender for a diet coke in a double old fashion glass. I squeezed a lime in it and no one asked me a thing the whole night. Everyone just assumed it was a drink. Someone did ask if I wanted a shot, I just held up my glass of diet coke (which they weren't prevy to) and said I got my drink for the night, thanks! And that was the end of the conversation.