^ That waiver is not worth the piece of paper that it is printed on. You cannot sign away "gross negligence". Having a protective measure in place or knowing of a protective measure that could reasonably be taken, and then failing to provide that protective measure, and as a result someone gets hurt ... puts one into a difficult legal position that the waiver won't protect against.
I think it's time to wrap up this thread. If this thread makes someone ask questions at their next track day, it served a purpose. If this thread makes trackday providers think about and implement protective measures, it served a purpose. If you are at a track day and you see something that is not right, point it out to the organizers. Better yet, if possible, do something about it yourself. Volunteer to drag hay bales around. Volunteer someone to be a corner worker. If a certain track day provider does their job well, go to another one that they organize. Conversely, if another track day provider does not do a good job, point out the issue to them and if their response is nonchalant, stop going to those and find another organizer until they shape up. Money talks.