I would be surprised to learn that her family, friends, fourth-order cousins, youtube real ultimate fans, etc -- or anyone else who would self-identify as "bereaved" signed any sort of waiver, and Jenny had no power to sign away these peoples' rights.
Plus anyone in the bereaved class can file any sort of suit they wish, waiver or no. That's what the insurance is for. To defend against the nonsense that a flying-related death generates.
It's been a minute, but I think our worst was a plane of ours went and got itself mid-aired, and it generated somewhere around 17 lawsuits against us. We did not train the pilot, nor his pilot-rated passenger, but I assume a token checkout was performed. The plaintiff's lawyers were a shower of low-grade ambulance chasery and embarassment. One of them thought he was there for a boat crash. Several were there for people who had seen or heard of the crash and now were traumatized in a way that required large cash settlements to resolve.