There was a time, and I can't recall where or when, but the buffet was meant to be just one course - so one trip to select your salad items. But then I saw where the hot food was also include to the one course trip. Customers were given one plate and staff could tell you hadn't been if your plate was clean. Of course if you licked your plate clean you might get away with it!! Haven't seen these single trip places for a long time now. Decades I'm sure.