What it does highlight and something that is easily rectifiable from an H&S perspective, if Staff are standing around one of them could shout 'fore' down a megaphone when somebody has hit the ball with their bat.
Or they could hold up signs or something.
The other thing that bothers me is that other people saw the ball coming down (or might have seen) and it makes you wonder why somebody didn't throw an arm out (unless nobody was paying attention).
However, I'm not into this bat and ball game so don't know how fast this can happen but I've been at a cricket match where somebody hit the ball with their racket and I caught it in the seats.