It's about the freedom of learning without the ropes and harnesses of our society all of the time.
True story, I know a kid who was running barefoot in the neighborhood growing up and stepped on a rusty nail. Long story short, it led to complications and he had his foot amputated at some point. Now, I let my kids run around the neighborhood all of the time, even though they own lightweight, comfortable shoes (that cost well in excess of $20). Why would I do that knowing that they could get hurt?
I think this must just be a difference in perspective that we might have and I'm okay to agree to disagree.
I am curious though, do your kids have cell phones with internet access (really am just curious if my theory holds correct)?