I've had problems with this three times in the past three months. In each case, I called reservations and was told the hotel was 100% booked. Then, the day of the "event" I called and they magically had a room. So they couldn't have been 100% occupancy at the time I wanted a reservation. So I called and quizzed a supervisor and found out that hotels can now self-enter an event that excludes the Platinum guaranteed reservation. There is no one supervising this, so the hotel can do it at will. Without any occupancy verification. In all three cases I was checking on, it looks like the attempt was to book at the highest rate possible the most rooms possible and use the Marriott system against itself. I'm really upset about this because it defeats the purpose of the Platinum guarantee. Totally.