I do have children, and from that perspective: She is not crazy. What she's describing is what we would call normal life in most of Europe. I'm sure it's also normal in more small town US. The kind of crazy incident she describes sounds like a New York, or other big city kind of thing.
It’s difficult to detect a consistent trend in the US: most of the anecdotes in this thread are about people being accused of endangering their children in small, suburban communities.
As a personal anecdote: I grew up in NYC, and was riding the subway alone by the time I was 8 or 9. I believe there’s also around when my school gave me a free metrocard to travel on my own, and I believe that program is still in place. Most of my NYC friends had similar experiences.
