That form also exists. It is a liability waiver, and you need to sign it before classes or any dive using a commercial operator. As I mentioned before, they have been challenged successfully in the past because of the idea of informed consent.Why not just have them sign a generic release form? Here you go:
Diving can kill or injure you. If you die or are in any way injured by your free choice to come diving with us, that is all on you. We have no obligation to prevent you from being injured or killed and no obligations to pay for anything or do anything if you happen to be injured or killed today.