I had a trampoline growing up and before any friends could go on it, my mom had their parents sign a liability release statement. Despite that (probably not an issue now because more people have them), I did not enjoy having it. When friends came over all they ever wanted to do was jump on that trampoline, but that was back in the 70s. Getting that too, my dad increased his umbrella liability coverage to 2 million. My son wanted to get a trampoline, but I said no. I didn't want to be supervising kids jumping on it. I didn't want to have to check with my insurance company to make sure they allow this (and possibly even have to search for another insurance company.). I didn't want to get liability statements from parents of kids that come over. I have an only child and I didn't want him jumping on it with no one around and I didn't want to spend hours out there watching him jump. I didn't want to up my umbrella liability coverage. It might not again today be a problem, but I didn't want kids just wanting to jump on the trampoline when they came over to our house to the exclusion of other fun activities based on my negative experiences as a kid. Also, I think they are too dangerous. As another poster alluded too there are lots of possibilities for accidents with multiple kids jumping on one together and that's what kids always want to do. I didn't want to turn into a babysitter and a policeman. Many people I'm sure think they are great to have. If my son wants one, though, he'll have to wait till he has his own house. My husband supported me on the decision (which I greatly appreciated), so we were united in turning down my son's request.