I can echo many of the sentiments above.

I think parents are made more aware of the (false) dangers facing kids. Also I think there is a deep subconscious social thing going on. What I mean is that if your kid is out playing someplace that he's "not supposed to" according to the substructure sensibilities of other parents, you'll be to blame even if only in your own mind. However, 50 years ago, if a kid got hurt playing on the Monkey bars, it's not your fault as a parent, bad things just happen.