I wish I knew. My children have had the cops called on them for playing in our front yard. I wish they could spend their afternoons climbing trees and playing in the grass like I did growing up, but there's a group of people who see children playing outside of direct parent supervision as a categorically dangerous activity.
I'm always struck when I take my kids to school and see the high schoolers gathered around waiting for their bus to pick them up. You wouldn't even know they exist otherwise - there's no other signs of their existence, no groups of them playing at the park, no sounds of games in the streets, no hoots or hollers from down the block - just nothing, silence. Each house is an island and each teen a castaway from 4pm when they get home to 7am when they leave for school, severed from the neighborhood and each other while the same folks say, "How come kids don't play outside anymore?"