Confluence 6.0.1 introduces the option out-of-the-box for to copy a page including all child pages. There is an option to copy all of the attachments on those pages as well in the form of a checkbox that is selected by default: Attached files and images

Administrators of large Confluence environments have requested the option to un-select this checkbox by default as copying large page trees with a lot of attachments can quickly fill up disk space.

This suggestion is tangentially related to CONFSERVER-6415, which is a request to allow admins to set a max size limit to a space.