Couple more thoughts.
If you saw those three crashes at one event, I would probably avoid those organizers. I've seen an much as one crash every 2 events but usually less often.
Also, no one should be driving 10/10 at a driver's ed event. You should be driving 8/10 so you have some leeway if you hit a slick patch or other hazard. Also, if the track organizers notice more than one or two cars going off during a session, they should get the drivers back together and have a little "chat."
It's in their best interest to maintain the insurance for the event. Finally, the corner workers should be reporting drivers who seem to be driving too hard or taking too many risks. Event organizers can't prevent all mishaps but they should have a pretty good handle as to what's going on and if things are getting out of control bring it back in.