Well - let me add my 2 cents here. Recently there were quite a few "auctions" on Ebay for Hyatt 5,000 points that were given out during last year's joint promotion with Mastercard. Unfortunately, Hyatt staff didn't control these 5,000 point certificates propertly - using one single code for the promotion without any serial number. Some people, apparently including a Hyatt employee, had figured this out and were selling these codes on Ebay. Subsequently, Hyatt traced all the people who redeemed these certificates but had not won the 5,000 points in the promotion and pulled the points from their accounts. So it was a major mess with lots of problems created for both Hyatt and Ebay.