Man, this sucks. I feel badly for this guy.
I hate leaving my keys with mechanics, etc., but it can't be avoided. I try to tell myself that I'm only being paranoid, and that these people are supervised professionals, but then you read stories like this.
I wonder how many times my car has been pushed hard, etc. at the hands of the BMW grease monkeys . . . I seriously doubt that they roll around like choir boys in a stranger's M3.