Once more, courtesy of Overheard in NY:

Lady: Do you have a sushi menu?
Waiter: This is a Chinese restaurant.
Lady: …So no sushi?

–Suzie’s, Bleecker Street

This does happen. My parents used to run a small Malaysian restaurant and someone once came in and said, “I don’t suppose you sell fish-n-chips?” And then as if a light bulb just came on, he answered his own question, “No, guess not.”