I caught two people working this scam while in Boston near the convention center. They watch for a group heading toward the revolving doors. One person gets ahead of you and the other right behind you. As you approach the door, the person in front slows down and, on going through the door, his packages or his bag get jammed in the door. You bump into him and the person behind you bumps into you. When the person in back “bumps” into you, they lift your wallet out of your back pocket – or out of your purse (most women tend to push their purse back, behind their shoulder when going through a revolving door). As soon as everyone is through the door, the person with the wallet hands it off to a third person going a different direction (in case you immediately notice your wallet is missing). Then they all split up, only to reunite later to share your cash and credit cards.