The currency exchanges would be ridiculous. The security of the S&S cards is not good. They don't ask for any verification. When the receipt comes for your signature, the name of the person who is assigned to that card, the card number and the cabin number are all pre-printed on it. Just sign whatever name is on it, and they'll take it. The good thing is that certain waiters and bartenders did learn our names on the 1st day. That made me feel a lot more comfortable. And of course, check the tab frequently for any phony charges, they have the signed receipts, it should be obvious the signature is not yours. But what a pain; I hope nobody ever has to deal with this. Don't lose your card and don't leave any receipts lying around. You'd have to be pretty bold to charge something on another person's charge just to save $5. Leaving the room number off the receipt and requiring the guest to provide that as well, would eliminate the risk.