Seriously though, I've coached youth football for two decades and I don't think I've had any kids suffer from a concussion. I've had bone breaks, sprains, etc., but never had a kid get 'dinged' like that, either witnessed it nor had any child come from the field, bench, etc., and complain of any head injury, dizziness or the like. If I did, I would report it to the proper channels, including their parents and they wouldn't play again that season uless there was a doctor visit and a note from him/her saying it was OK.
I know the county parks & rec division, et al. are in the process of protocols, rules, etc. for such occurences.
Amazingly until just this past year, the subject has never been brought up.