And if you don't have those, a lot of buildings have common patterns. Its very much in the realm of possibility to train a model using exterior and interior information so that you could have AI generate a floor plan using only exterior data.
Combine that with a small drone that could fly around a building and take different wifi signal readings to triangulate access point positions.
Once you have all that don't you have everything you need to detect movement in the building based on signal disruptions?
Yes, seems like a bit of work but it absolutely seems like the type of effort some governments would put effort into.
