What I recall--and this goes back to perhaps the year 2002 or thereabouts when there were consultations, on the west coast in particular--is that it was the view of the legal community there that these waivers, if they were properly executed, would indeed operate validly and be upheld by a court as proof that the individuals who signed them have voluntarily undertaken the risk associated with the adventure.
Now, I think it's case by case. It would be up to the courts to decide in any given case the manner in which the waivers were established and whether or not they would actually be effective in any given situation, but it is part of the package deal, if I can put it that way, in the legislation. There's no doubt about that.