Some societies allow kids to go up and play on the roof; others strictly prohibit it. If the railings are low, gaps are wide, or the parapet isn’t very strong, letting children run around freely there is worrying.
Asking about the rule tells you two things: one, how safe the roof actually is; two, how seriously the society treats risk. A building with strict “no play on terrace” rules might be annoying for kids, but it does show they’re cautious about accidents.
If kids are often seen playing unsupervised in a clearly unsafe setup, that hints at a more relaxed attitude to safety overall.
