Unattached simply means that the songs are not in any playlist. So, from the player's front panel (in your car for example) those songs would be unavailable. Likewise, HiJack will only show what is in a playlist. I guess you could "stash" stuff you don't want appearing all the time (sound effects, holiday music) but once you get 2.00 installed (sounds like you may want to wait for a non-beta version) you can set up filters.