Heard many people mention this after the show, I was watching the band so I never saw it, but it made it onto the local news. So far no explanation has been given.
http://youtu.be/mHe0X_GMOMA
YouTube - blitzburwell's Channel
Shows how this may indeed be the most intimate show of the tour, the stage makes the stadium look quite small. Not a bad seat in the house.
TRAX normally adjusts schedules for large events so I would think so, however I am doing some digging to find out because it sounds like it will be a nightmare after the show trying to get out of there.
I doubt they will be rehearsing in SLC, they will be staying in L.A. and will probably be rehearsing there, although they will have a soundcheck in Salt Lake.
Salt Lake City sunset will be about 8:54 p.m., so there will be some light, but won't last very long. Fyi, average temperature for June 3, 2010 in Salt Lake City is 77 degrees.