When I was a kid, we all rode bikes...everywhere. We went on road, off road, built our own Evil Knievel ramps at the bottom of hills to jump as far as we could, crashed often, went way too fast, didn't pay attention much to traffic signs and many times, put more people on one bike than belonged on one bike. No one wore helmets (except the special kid down the block who always wore a Green Bay Packers helmet in Bears country. No one cared, we accepted him anyways) and, with the exception of someone who knew someone who knew someone who knew someone, no one got a brain injury. Then they came out with bike helmets...for the children. To save them from brain injuries.
Now fewer kids ride bikes. They sit indoors playing Pro BMX on XBOX and have that indoor, sickly look of POW's. We've done an awesome job of protecting the children from sunlight, fresh air and exercise.