Only the high value suspicious ones. If a residence in a high value area is claimed as occupied, but no one put it on their drivers licenses/ID or any other existing government interaction then request additional documentation. Let neighbors report vacant property and require multi-family building administrators to report suspiciously under utilized units.
in the age of deep learning, streetview and daily satellite images it should be possible to determine automatically. Of course such an operation opens the door to all sorts of surveillance.