For about the 900 millionth time there are options for "kids" to play airsoft. From games where they're supervised by a parent via buddy system style play to entire leagues that are all kids.
The reality is that kids are not responsible (18 isn't much better to be honest but that's the law of the land). In game they're annoying and unsupervised they're playing in a park and the police arrive leading to a news story and the Canadian Assoc of Police Chiefs calling for a blanket ban or they're just shot dead and all the mothers are wringing their hands.
The current self regulating system works very well. And the only thing under aged players need to do is wait. Airsoft won't be gone in a month and they won't have missed out; it's not a fad.
Airsoft, where nothing is hurt but feelings.