Boys will be boys I guess. Some men will tell you they did stuff like that or more dangerous as a child/teen. Some continue to have dangerous jobs, sports, hobbies. I've dated pilots and their jobs scare me sometimes because they fly all the time so they are bound to have at least one scary story to tell. I was not afraid for the guy that worked at a nuclear plant, but it felt like I should.
To answer your question better, I would probably date him until he tells me something like he was jumping over a building once and barely made it to the other side. There is really no good reason to have such a hobby but some hobbies are dangerous. Another guy liked skydiving and whitewater rafting/kayaking over some dangerous waters. Forget that, but I would still date him.