Cars, and the entitled culture we have fostered around them, make streets hostile to pedestrians and likely fatal to small children, even if children followed the laws and common sense. I experience it practically daily. Every time I cross the street at a marked intersection, cars will stop for me 9/10 times. At unmarked intersections, its more like 5/10. Crossing at a stoplight with a walk signal on is still precarious because of the tendency of many drivers to blow through crosswalks without stopping so they can turn right on red. Every single day I experience a situation that could be fatal to a less visible child with a more fragile body and slightly worse situational awareness. No way.
The second problem is the CPS story. My neighborhood is extremely safe, but the parents here are borderline psychotic about helicoptering their way through their children's lives. Every time I take my kid to a playground, I end up witnessing helicopter parents freaking out about how my kid will climb a ladder by himself or jump off of a piece of equipment by himself... sometimes they swoop in to "parent" for me...and other times they will chew me out for being so irresponsible as to let my kid learn his own boundaries. As much as I respect the mission of CPS, I've heard enough horror stories about their enforcement of parenting methodology that I wouldn't ever risk having them called because my kid walked to the park by himself.
It's a shame.