I took part in an autocross in Mass at an airforce base in which there was a long straightaway where you go up to about 60-70 before have to break hard and do a 180. Directly behind this 180 was a main afb road so they put up jersey barriers to separate the road from the track.
This guy had a race prepped Mustang Cobra and he popped a front brake caliper bolt going down the straight. He lost his front brakes and could not stop, plowed into the barriers launching them clear across two lanes, and he as well as two barriers ended up on the far side of the road. Luckily, there were a bunch of military guys sitting on the barriers watching the races and they all scrambled to safety.
The Mass state police came out as well as two of the afb fire engines to survey the scene. There was no fire and the car had a full roll cage, five point harness, and air bags. The guy was also wearing a helmet. Fortunately, there were no injuries and this was the last time the club was allowed to use the base due to liability concerns.
I guess one never knows when something like this can happen even in a 'safe/race' environment. Then again, there are far too many people in the world who lack common sense and get into trouble because of it - sometimes death resulting. Very unfortunate.