I'll be very, very curious to see if Michael Bay can explain or justify using an extra with no stunt driving experience in a Transformers 3 scene--which resulted in her getting a metal object through her skull. She was making $25, though it seems she got pretty good medical care in the wake of the accident. The studio maintains that it was a freak accident and she wasn't involved in the stunt going on at the time of the accident, but it's still hard to figure out how this could have gone down. Nikki Finke quotes a source who suggests the situation must have been the result of serious violations of industry standards.
Bay's casting announcement for extras in the part of the movie being shot in Washington, D.C. also notes that it's a good thing if folks trying out have their own cars and precision driving experience, which suggests that this kind of practice isn't a one-off for Bay. Given that Transformers: Revenge of the Fallen had a $200 million budget, you'd think Bay could afford a little bit more than $25 up-front for people doing stunts. Maybe he will now.
The Screen Actors' Guild has a safety division with helpful bulletins and guidelines on set safety. But it does seem like the safety-oriented rights are aimed more at actors than the stuntmen who stand in for them. Even so, you'd think directors and crews would want to do their best to exercise common sense--and common consideration, especially for people who are excited to be working for them and happy to do it for very little money.