thats interesting. i had noticed something like this. Im not sure of an easy solution but parents could more directly engage in relationship building and navigating their communities with thier children so there would be more trust but i feel theres been a fear epidemic (whether justified or not) and its not likely that perceptions of safeness of the community will change. people such as gatto and peterson have talked about unsupervised play as being necessary for orientation of the world fir children. 

 I agree we have to get to know our neighbors.  That's crucial.

The way to break the fear culture may be to create bubbles of a counter-culture.  Maybe we should make a point to move so as to be near like-minded families.  If there is no consensus favoring unsupervised play, we have to build one, and let it spill naturally out into our communities.