you're right unfortunately it doesn't work well for child sites because page guids must be unique per installation. The system was really designed for initial installation of a single site with some default content. I will create a wish list item for this in my project tracker to figure out a better way to wire up initial content in child sites.
it works ok now if you don't use child pages and only have a few root level pages because then it does not matter if the page guids get changed.
Best,
Joe