NEW YORK (AdAge.com)—Joseph, a 30-something New Yorker, was visiting Harrah’s Resort in Atlantic City on a weekend the hotel was booked solid. But after using his Total Rewards card while playing the tables, he was directed by a pit boss to the front desk, which informed him a room had become available for a “special rate of around $100 a night.” When he checked out two nights later he was told all the room charges were on the house.Was the sudden vacancy pure luck or was it just a case of good customer-relationship....