When they flip it over to sit and rock in it, it has happened. My sons will squash their own fingers and have bonked themselves in the forehead from sitting and rocking too fast. It’s still an awesome product.
I bought the felt curvy board and feel very comfortable using it on my wood floors with no issue. It also works fine on the rug but picks up hair and lint sometimes. Only downside, my kids use it as a slide when propped on the couch and the felt causes some friction making it a slow slide.