So the answer is that the enterprise is straight outta luck for all their documents? I think this is a choice that the IT admin should be able to make.
Back to the home users (who I care about), the exciting promise of Libraries is dissapointingly deflated by not allowing us to index any folders on a NAS. Windows Media Player still does its separate thing, crawling the drive (which is the only way to get my music, vids, and pics into Libraries, though slow/crappy and it doesn't work for documents). Photo galleries also do their separate thing crawling the drive.
Please, all my stuff is on a NAS, and not everyone is going to have Windows Home Server or another actual Windows PC for their file storage. We need to have the ability to simply index networked drives and add them to our Libraries.