Hiding spots change. Tree hut => storm => pile of boards and junk under a fallen tree.
Hey, Mr. Whatshisname in Somewhereidontknowabout bought a new car and/or parked it in a different spot.
Inside buildings? Even worse.
Companies moving from one place to another, leaving empty buildings. People changing furniture or remodeling. Simply hanging up a mirror would change the whole scene, since you can then see spots you couldn’t see without it.
The idea is great, but it’s impossible to accomplish, at least for now.
Maybe future technology would make it possible to monitor everything and updating it without too much trouble.
Work on the idea some more and wait 20 years or so. Who knows?