It's late. You are in your hotel room getting ready to get some rest after a long flight, a full day of business or hours of sightseeing in a new city. The phone rings. It's the desk requesting confirmation on your credit card number and expiration date. You provide the information; give a fleeting thought to wondering why they can't keep these numbers straight and go to sleep. Your next credit card statement arrives full of charges you never made. It wasn't the front desk calling after all.
Like all effective scams, this one is simple, does not arouse suspicion and gives the thieves a wide window in which to work. Unless the charges they make are so out-of-the-ordinary that your credit card company's interest is piqued, they may have weeks to enjoy spending your money.
Of course you can dispute these charges but why go through the hell that can entail? Don't put yourself in a position to have your credit card rejected because your limit has been used up by someone else.
Never give out any credit card information on an incoming call. Asking for a number to call back is not enough. Clever thieves will come up with one. Independently acquire the number and call it. If you find out that the call was a scam, report it to the front desk immediately.