I once got one of these up to speed (solo) at the park near my home, jumped on, and held onto the middle with my legs, while my head spun around past the outer platform. Then, some dickhead bully hit me in the back of the head with a rock and I had to make my way home while bleeding... Only, there was literally no one there. I checked multiple times, and there was nowhere to hide or run to. That fucking merry-go-round dislodged a rock from under it, then the centrifugal force flung it right at my head! And that's one of the milder ways you could hurt yourself on these things...