I know better, but I once did that very thing in Buenos Aires. In Santiago, Chile. He expresses delight and calls the object to the traveler's attention. The curtain is going up and the traveler is being invited to participate in the performance. Sure, that sounds ridiculous when you read it here but for many people it seems to make sense when the scam is underway.
Greed moves mountains.
Play along for a while if you want some amusement and can stay in a public place, but be ready to bail out fast. He walks off and poses in front of St. Peter's. Always a good neighbor, you frame, focus, and, carefully immortalize him on film. Suddenly, he turns and sprints down an alley out of sight. You're puzzled, at least until you turn around and discover that his accomplice has slipped up behind you and disappeared with your day pack, camera, or whatever you set down to do the favor.