Let me start letting it be known I'm not saying shuffle play doesn't work in offline server mode. It works fine. The 'problem' is that shuffle play won't work unless I still have a wifi or 3G connection. I don't know if this is a kind of bug or if this was intentional, but I find this kind of annoying as I don't like to have my 3G or wifi constantly. It will work if you don't have a network connection after you've already started shuffle play then disconnect.
I know I could just use a different music player for this, but why bother? Subsonic is all I've used to listen to my music collection for the most part. I just want to be able to use it when I don't feel like needing my 3G.