Probably a factor Friday, but best explanation I've heard was every UOR TM got a free "guest" ticket that was good for a ridiculously limited number of nights (someone said five, but that may have been an exaggeration). Final Friday/Saturday were two of those nights. Throw in two nights of final B&T shows that brought out every FFPholder, increase in international guests who don't really know Halloween has passed, it was packed. Over triple projections on Friday.
By the way, how busy was Friday? They actually put a moratorium on photos in Invasion. Full queue in Fast Food Blvd. was in use (didn't even see that opening day), with the line at Mel's literally out the door. It was a peak night.