'82 survivor over here. Got knocked unconscious while playing more times than I can recall. It got to the point where waking up on my back surrounded by aghast lookie-loos became so commonplace I stopped giving a damn, so as long as I could manage to stand up and walk I considered myself to be fine. Then again, my parents were the type of people to hand me a box of band-aids when I got hit by a car and lost most of the skin on one side of my legs, so...y'know, my experience probably isn't typical for most kids. But still, I lived, and I'm (if anything) tough as hell for having done so. In spite of the multiple concussions, copious loss of blood, near-drownings, assault, and murder attempts (no, really, my neighborhood was awesome) I think I turned out okay... >_>
Yes, you should support your kids, and do your damnedest to make sure they actually manage to make it to that stage of life we call "grown up" with the majority of their mental/physical faculties in tact. I just think parents need to realize that they aren't their child's best friend and that they can't be their guardian angel forever, and that that's okay. Just try to raise them to keep the incidents of utter crashing stupidity to a minimum and they'll probably come through okay.