My husband and I took our boys, 10 and 12, to New York this fall.  My kids like to visit big cities, having spent a lot of time in Paris, Chicago, and Munich (OK not so big).  After arriving in Penn Station at 9:30 p.m. my youngest did stride confidently and alone toward a men’s restroom until I caught up with him to say that, here in New York City, he had to be accompanied by a parent to public bathrooms at night.  He wasn’t being so much naïve about safety as he was sure he could deal with whatever might arise.  So I told him he was wrong.  I lived in New York City when I was a young child (ages 3-5), and I was taught otherwise.