Also your minor children. Courts have held that your waiver does not and could never apply to them. I saw a dive shop here in NJ driven bankrupt and closed despite the dead diver's waiver, based on a suit brought by the diver's spouse in the name of the children. They were awarded serious money because he was a young professional. He drowned in a small inlet, about 8 feet of water. My recollection is that he was found tangled in the remains of an old RR bridge that he was not supposed to go near. It appears that fishing lines and a strong current at the narrow bottleneck under the bridge pulled the regulator out of his mouth. He was on his certification open water checkout. Visibility there is limited. It can take only seconds for a panicked new diver to die in that kind of situation.
In that case I am pretty sure that the fact that the children were involved had little to do with it. The liability waiver will absolve the operator or instructor in most cases that arise in typical diving situations, but not in cases of gross negligence or violation of accepted standards. If he had been a certified diver hopping of the boat and then going where he was warned not to go, then I doubt there would have been a case. It is different, however, when you are talking about scuba instruction. Instructors are held to very stringent standards, and if an instructor intentionally put a student into a situation as dangerous as you say and did not maintain close supervision and control at all times, then the liability waiver will not be much help. I would assume the instructor was also expelled from his or her agency. There was a similar situation in Virgina this summer.