Michael Shermer in The Scientific American:
On a Los Angeles street corner in 2000, I was the “inside man” in a classic con game called the pigeon drop. A magician named Dan Harlan orchestrated it for a television series I co-hosted called Exploring the Unknown (type “Shermer, con games” into Google). Our pigeon was a man from whom I asked directions to the local hospital while Dan (the “outside man”) moved in and appeared to find a wallet full of cash on the ground. After it was established that the wallet belonged to neither of us and appeared to have about $3,000 in it, Dan announced that we should split the money three ways.
I objected on moral grounds, insisting that we ask around first, which Dan agreed to do only after I put the cash in an envelope and secretly switched it for an envelope with magazine pages stuffed in it. Before he left on his moral crusade, however, Dan insisted that we each give him some collateral (“How do I know you two won't just take off with the money while I'm gone?”). I enthusiastically offered $50 and suggested that the pigeon do the same. He hesitated, so I handed him the sealed envelope full of what he believed was the cash (but was actually magazine pages), which he then tucked safely into his pocket as he willingly handed over to Dan his entire wallet, credit cards and ID. A few minutes after Dan left, I acted agitated and took off in search of him, leaving the pigeon standing on the street corner with a phony envelope and no wallet!