They claim they never made the purchase or their account was hacked, even when it was delivered to their address. The Credit card companies seem extremely soft on this. Credit card companies take the money from PP, and PP from the seller. It can still be done with G&S, but it seems PP will then cover your loss with their seller protection.
It's a trick that likely can not be used more than once by the same person(or at least very infrequently), so they often take out many at one time, and it can be months after the deal, leaving sellers to have to come up with money to get their PP account back in balance. It's a nightmare even with G&S. Said by someone that has just read about it, not the pain of experiencing.
There was a thread in the stickies, but I don't see it anymore