It all because of the blame culture. Someone can sign all the disclaimers in the world, and take all the precautions imaginable, and we can have stringent safety checks, a driver briefing and a trained medic crew on standby.... but... if someone has a massive crash there's nothing to stop the family of the injured/dead person for looking for someone to blame (and a nice fat payout). If that happens it would literally kill the magazine, and I'd face the very real risk of going to prison.
Understandably I don't want to go to prison!
To give you an example of how extreme things are - I was in talks with our insurers, and our legal team about doing a 200mph run with a couple of people including Rod. They stipulated that a professional mechanic had to check the car over thoroughly before any runs were attempted. When I stated that Mark Shead would be there and there's no one in the world who knows the car better than him, that wasn't enough, and they STILL wanted a mechanic there.
In this day and age big business simply don't want to expose themselves to risk. And a thrash is a BIG risk!