Can book outline administration be restricted to within each vsite?

The Books settings page at admin/content/book/settings states that "Users with the administer book outlines permission can add all content types." This is a great feature allowing for users easily group content within their vsite, but it appears to be circumventing the vsite mechanism. With this permission enabled, each and every user appears to have access to (and the ability to add pages!) to any other users book outlines - even when the edit and delete book content permissions are restricted to "own" and explicitly unchecked for "any." This would appear contrary to the idea of virtual sites where there is usually an expectation of isolation of content between user accounts; have I possibly misconfigured something that is breaking the inherent separation or security between virtual sites and individual user accounts? If not, is there a way to easily change this so that users can use book outlines with all content types, but only within their own vsite?

The "scholar booklets" features does seem to preserve isolation between accounts (without requiring the "administer book outlines" permission), but even though overriding the strongarm settings for Books settings can allow the selection of multiple content types for which outlines are allowed (via checkboxes), there is only a single default child page type (radio button) that can be set. With only a single default child page type, it wouldn't seem to matter what other (multiple) types might be checked in the "allowed book outline types" section because the "add child" link in the content page is always going to force a pre-determined and single page type regardless of the content type(s) (set as "allowed") to which the child is being added.

I would prefer the flexibility of using the book outline mechanism with any content type but within a traditional virtual-site context where individual users attempting to create their own book outline content don't see or have access to every other book outline page created by every virtual-site user in the system. Is this easily possible? Thanks in advance for any clarification or suggestions on how this might possibly be achieved.