I regularly forget that I don't have wifi enabled when attaching to the subsonic server from my android phone at home.
After a few error attempts I start to wonder if my media server has gone to sleep, so I jump over to my xbmc app that has a feature to wake up the server. That app is kind enough to immediately inform me that "Wifi disabled - This host is Wifi only. Should I activate Wifi?"
Feeling sheepish, I turn on wifi and jump back to the subsonic app and everything's working (naturally).
So - feature request for the android app - please sense if wifi is disabled for a wifi-only server definition, then warn as above.