But I think the main point of the whole supporting 18+ rule is that when a person is 18, he/she can be held LEGALLY responsible for their doings. Anything goes wrong at a field, they can be PERSONALLY be held responsible, and not their parents.
YES, their parents can agree to take responsibility for their children's actions, but HEY, in reality, it's easier to point fingers to other people/things than to take the blame for your children's actions. (Just look at the bs examples of people/parents blaming violence on video games) I'm not saying all parents are like that, there are some responsible ones, but it can't be said for all of them.
And gosh, this is turning out to be an ethics debate. lol