Being a father of a 13 year old son who loves Call of Duty and other FPS games, kids need guidance, not rejection. For the long term growth of the sport, we should mentor them and teach the right way of owning firearms. We should give them a place to play and they will stop playing in the neighbourhood. By getting them to play in games with adults, they are going to learn the proper way of handing the guns. They are less likely to do stupid things with them.
I understand that most of us don't want to be babysitters as we want to play the game and be involved. But someone needs to sacrifice and teach them. We shouldn't be almighty about rejecting them. When we reject the kids, the kids are just going to use the gun to shoot his friends in an uncontrolled environment. There is no way treat future customers. We should allow limited kids to attend the games. If we are the mature adults that we claimed we are, kids will learn alot from interacting with us.
I am glad to see that my local field's minimum age is 13, and I would love to bring him when he visits me next.