I have, when I lived in NYC. It was lifted from my pocket though, not taken by an enterprising restaurant employee or the like. The thief basically took it to the closest subway station and bought as many prepaid subway passes as s/he could until I reported it. Those passes are as good as cash, pretty smart! I guess all you can do is use it sparingly, check your bills constantly, and avoid any websites or stores asking for information in a shady manner.
I did have the experience recently, after a large post-bonus shopping spree, of my c.card (MBNA) being held. When I phoned in to get the hold taken off I just had to give them the number and my name, ie the info on the card itself - no check of my mother's maiden name, my address or anything else - which I found alarming.
I did have the experience recently, after a large post-bonus shopping spree, of my c.card (MBNA) being held. When I phoned in to get the hold taken off I just had to give them the number and my name, ie the info on the card itself - no check of my mother's maiden name, my address or anything else - which I found alarming.