If people want to do something that puts their own life in danger, and they ought to have known the risks (ie.: in ethical jargon, they have both "moral compete

If people want to do something that puts their own life in danger, and they ought to have known the risks (ie.: in ethical jargon, they have both "moral competence" and autonomy), then that's their business. If people do things that can hurt other people, and these other people don't have a say in the matter, then with the exception of certain fiduciary-like situation, that's not okay.