Today's New York Times has an article about kids walking to school by themselves. My kids, being homeschooled, didn't face this specific conundrum, but we did allow them to start taking the T and walking places unescorted at pretty young ages - and we definitely faced disapproval from other parents about this. Fear of abduction is one of the most oft-cited reasons for not allowing children to walk places.
This little pair of facts is embedded in the story; I wish it had been a bit more prominent.
Critics say fears that children will be abducted by strangers are at a level unjustified by reality. About 115 children are kidnapped by strangers each year, according to federal statistics; 250,000 are injured in auto accidents.
The Federal Highway Administration has a program to encourage walking and biking to school, with suggestions on how to improve safety for pedestrians and bikers, and ways to allay parental fears. For the sake of our children, I hope it succeeds.