Yes, yet I can have a tree fall on me in the woods. I'm well aware of this fact, are they not?
If we as a society need to limit or end all brain injuries, then we should end all forms of recreation, sport, etc., that might cause one. Do they not know when they step on the field, whether it is for a game or practice, that they might get hit in such a way that they may never be the same? It could happen without being hit. Mike Gaddis blew a knee out with no contact. So did Jason White.
One can be hit by a bus crossing the street. Should we ban public transportation?