AdolfOliverBush, some guy did that once. He was dressed like a clown, did a magic trick, and said, "there's your trick." All the kids just stood there looking at him waiting for their candy. I didn't think he was serious, but he was because we got no candy from him.
I remember getting shit like oranges, cans of sodas, whole candy bars, peanuts, lots of Tootsie Rolls (which I disliked at the time), and candy from last year's Halloween (or Christmas... or Valentine's day)... and a "trick."