When you enter a "live" vvv town for the first time, you will occasionally see messages that appear to have hung over from the last vvv episode. If there is an active opposition guild in the town at that moment, they will usually also show in the 3 guild list. This doesn't happen if they hide/stealth or haven't actually gained points yet. However, when you DO see the message "unoccupied", it's because everyone, including you, is hidden or there are vvv enemies in the town and u better buff up..;p
Phrasing could be better - what it really means is that control of the town is contested. Hidden players no longer count towards control.