Two Maryland kids, ages 10 and 6, were picked up by cops on their walk from home and their parents investigated by CPS because they let them walk the one mile home. Here is the article:
The kids often carry cards saying "I am not lost. I am a free-range kid." but didn't have them on them this day. Their mother said, "The world is actually even safer than when I was a child, and I just want to give them the same freedom and independence that I had"
What do other US parents think?
For a little international perspective, in Kenya there are likely hundreds of thousands if not millions of kids this age running/walking to school.
In Switzerland at age 4 and 5 kids are encouraged to walk to school by themselves and teachers give kids saws to play on the playground with according to this article: http://www.cbsnews.com/news/why-my-child-will-be-your-childs-boss/
In NY and Philly, there are 11 year old kids everyday who navigate a complex system of buses and trains to go to schools many miles from their homes. There are many dangers in the world kids will face that we can't completely avoid with out stunting their development. The belief that there is a child molester lurking behind every tree is false.