It probably is due to a convention, but also because an entire block of rooms is blacked out for now--I tried to book a standard wing for May 2007 yesterday and all I could get was a garden view wing for $60 more per night. I asked why all the standard wings would be gone already and the CM said that an entire block of rooms was unavailable, probably due to the renovation of the rooms. I'm guessing he was referring to the North Wing.