Scrub commented about the reservation system. I wanted to comment but not diverge from Bill's Yellowstone thread.
It does create a huge problem for us because it may take a few days travelling to get to our destination. If we get delayed even once, every reservation after is lost.
Up here in Canada I heard that some travel agencies were booking large groups of sites. There are also groups of "permanant" residents staying in some of these sites. One of these residents were smoking pot throughout the day. I'm convinced my Wave heater was stolen at one of these campsites.