Here's what I've heard of. 100% underage games, kids of players who want in and are not boneheads. Played on a real field not some one's "big farm", and the parents all sit in and supervise. No regular players or folks not in the family at all.
As you can see, quite a logistical hurdle. You need a field owner who is receptive, a solid core of reliable players who have non-flaky kids who just quite aren't old enough.
This is also a once a year type event rather than a regular slot.
Airsoft, where nothing is hurt but feelings.