Okay, so not my area of expertise, but here's what's worked in my experience. The DRM content has a license that says how many computers and how many Zunes it can be played on. So, like, at my house, all my DRM music is on one PC, but I usually play it through my Media Center PC in another room. The first time I did that, I needed to connect and acquire a license for the second PC; that was done through Zunetag. But once the license is acquired, it lives on the PC.
You can connect as a guest and put Zune Pass music on the guest Zune; I do that all the time for my kid. His Zune's home is his PC at home; I bring his Zune to work, connect as a guest, load it up with Zune Pass content, and then bring it home. The Zune Pass music is associated with a different Zune tag (my special work one).
Does that answer enough of your question?
Jessica Zahn, Zune Social Program Manager ~ This posting is provided as-is with no warranties, and confers no rights.