...an apparently parents will let them. When Zander was little, I used to look at older children (usually of the male variety) doing stuff like this and think, "How could their parents let them run wild like that?" And now, here we are.
For the record, Zander went on from this roof-top adventure to have his first sleepover at a friend's house. It was an impromptu decision, which was definitely best for me -- no extra time for worrying. He loved it and now we're onto a new era. Anyone want a soon-to-be five-year-old for a night?)