Because I am a masochist, I read too much stupid shit on the internet. I continue to be amazed at how many people think sending 11-year-olds outside without adult supervision just can't be done because "times have changed" and there are "perverts" lurking behind every blade of grass.
I thought this was what all of those gated and limited access road suburban communities were all about. Safe! Cul-de-sacs! Children outside playing!
I live in the urban hellhole, a place that looms large in the imagination of many of these people, where death is around every corner and the subway is a one way ride to hell. I'm not going to tell people how to parent. Every kid is different, every parent-child relationship is different. If you don't think your kids can handle being unsupervised, safely and in a way that you're comfortable with, fine. That's your judgment call.
But, really, kids don't actually get abducted from the subway, or at all by strangers, very often. By the time they're in 5th grade or so, most should be able manage to walk down a sidewalk without running out in front of traffic. This task should be at least as safe as being driven down the highway at 65 miles per hour.