Then they can just as easily put their feet back on the ground and stand up again and get off the hook.
I’d bank on a prank gone wrong in this case.
I think you're right.
However, I can imagine a child slipping on a hard floor, falling backward, catching his collar on the hook and hitting his head, panicking, etc. I'm not saying it's the most likely thing, of course, but freak accidents that nobody expected do happen.