Well my gf got a Kobo Touch yesterday (from me

) and she signed up with a brand new kobo account. She bought a couple books and stuff, then I got the idea to hook it up to MY computer and load up Digital Editions to see if I could put my books onto her device. Well, it worked. She can read my Adobe DRM books even though the Kobo user account on her device isn't the same as mine. It does show that her Digital Editions authorization is my email address though, so I guess that is all you need.
It's a good way to share books with a friend