It really is a sad commentary on our society today. I would think it was probably some kids who were bored and don't know what to do with themselves outside.
When we were kids we played outside all the time, every damn day, we couldn't get enough. I don't want to go on a tangent here, but we went from morning til night. Riding our bikes, baseball (sandlot), wiffleball, football; especially fun in the snow, lol.
We would race our own built go carts made from big wheels, scooters and other various parts we could find, down the block and crash up, in the street no less!.
In general we would just always be out, chillin' with music (not an ipod in our own little world, but all together!), bs'ing on somebody's front stoop, hanging out at the corner deli, park, etc. We didn't want to be inside at all.
I also agree with Stu on the parents being able to keep us in line. If someone else's parent had to correct us or give a warning it was fine. People on the block helped keep the kids in line. And the thing is, we all felt safe. We could be out all day and it wasn't a problem. They had to call us in to eat cause all we wanted to do was play and be with our friends.
Anyway, I'm rambling guys, enough for now on this subject.