Yeah, I have the constant battle with getting my daughter to come home on time. It's loads of fun, has lead to her being grounded several times now. Making them check in once an hour has helped enormously with that problem, because she hates it when she is confined to her own yard. Harder to find someone to play with that way, since a lot of the neighborhood kids are the lazy types.
They aren't allowed to go inside anyone's house, and they have to tell me exactly where they will be. There are some pretty foul little monsters running around my neighborhood.