I think some of this falls into the category of obvious risk versus hidden risk. When I was a kid, I was playing in the park with some other kids who were dropp

I think some of this falls into the category of obvious risk versus hidden risk. When I was a kid, I was playing in the park with some other kids who were dropping through the bars of a dome-shaped jungle gym. I tried to follow, dropped through, and found myself hanging by my head, which had gotten wedged in the bars. I dangled there writhing around until my dad lifted me out about 10 seconds later. I had giant welts on the front and back of my head, and tore all the connective tissue in my forehead, I could wrinkle it up like a Klingon for years afterward. I think that particular jungle gym was removed after that.