I may be out of place here...
But these "minors" are the future of the sport and I think encouraging them is directly related to encouraging the sport.
Also, not everyone has the money to play at fields, entrance costs money that some people just don't have.
If my backyard was big enough I would play there, however it's not. So I play on land that friends of mine own. We are responsible and take every safety precaution. More so than any field would I'm sure.
I think it's a question of maturity, NOT age.