They are over night, private parites for high school seniors. I attended one my senior year in 1994. MK does close earlier those days to set up. Also, there could be many more teenagers in the parks that week. When we went down with my high school we went for a whole week and were in the various parks several days out of the week. My high school happened to stay off property. I don't know how many schools go to the parks during the week or stay on property.