I'd like to think I'll sit down with my son and lay everything out on the table regarding risks and concerns. And if he is still determined to play, then I won't be the one to stand in his way. His mother, on the other hand...
That was exactly my approach.
Something to consider, guys, while I like that theoretical concept....human beings in general are horrible at judging situations involving something definitely good now possibly causing something bad later. Children are even worse at it. They just can't grasp the concept of deferred outcomes. Not to say I'm opposed to kids playing football, but if your reasoning is that they made an informed choice...they really likely didn't, since they can't accurately judge that risk. Children regularly are tested in a "Have a piece of candy now, or 3 later" situations, and they take the 1 now.