No need to get all fired up on this, just check your statements carefully.

Last summer, I had two mysterious ticket purchases appear on my Amex statement. One on TAP Air Portugal and the other on some minor Spanish carrier. I disputed the charges. first one, the airline came back (through the cc) and asked me to sign a statement whereby I had not bought that ticket, and the charge (that had been on hold) was canceled. Second one, the airline never bothered answering and Amex simply canceled it.

In addition, there were also small charges that showed up on regular basis, both on my and my wife's cc, I believe from Brazil and for cell phone bills. After a few of these got canceled, they eventually stopped coming. I had my card replaced, but not my wife's.