Wow - I was at the Breitling Air Show today with my kids. It was a fantastic show (unfortunately bad weather, so we didn't get to see 'Jet Man' which would have been the kids highlight). This show was at an airfield located in a town (houses on every side) and the planes were flying every which way over the crowd. Had there been an accident like that, there would very likely have been many fatalities.
I was at an airshow in my late teens in Ottawa when almost the exact same thing happened to a P-51 flying there, but it crashed in a nearby golf course (about 100m from some golfers as it turned out later), nowhere near the crowd. The pilot was the only casualty then. They don't have the possibility here to stage them any safer thanks to the lay of the land. There is also a major highway about 200m alongside the airfield.
As much as it is amazing to watch machines in the air do amazing things, they have to come down one way or another...