I'm thinking about the "worst mother in America" who encourages her 9/10 year old son to find his own way home in New York. I'm thinking this boy is going to grow up with fantastic self reliance. I'm also thinking "If he grows up and doesn't gets abducted or killed"
I think it's serious. Parents can be the eye-lids of kids, and let the kids have their own sight/vision. Too much of freedom is also dangerous. I'm from India, as far as I know America is well-known for individual's(citizens) freedom. But, parenting need not have conflict with children's freedom.
Maybe it depends on the child. This boy kept asking to be left to find his way home. He was obviously mature for his years and confident in his own abilities. I think it was probably right in his case. He will probably go far - (if he takes the wrong bus!!)
Remember, even if it is a rather young human there still in a human network. They should be able to have these skills, especially if a young kid gets lost, then that means he doesn't give up and sit there and cry, he knows what to do. I am not saying this isn't dangerous, and I am not saying this is a good thing. I am saying that being able to IS a good thing. The age seems a bit young, I think it would be ok if a 12-14 year old did it. Its best if everyone knows how to and this age seems a little better then 9 or 10. It's risky but you need to learn this type of thing sometime in your life.