Lime from a Lemon: Sussing out the bartender

Since trying JC Wilson’s recipe I have become a big fan of the sidecar. It’s easy to make and tastes great at home. But whenever I order it in a bar it never measures up. Finally I asked a bartender how she made it. She admitted that she was trained to make it as a margarita with Brandy instead of Tequila.

So here is my question. How do you suss out a real bartender from one who doesn’t know a lime from a lemon?