definitly an atrocious violation of privacy, but in reality discerning between an animal, something blowing in the wind, and a person moving would be very hard without a dedicated calibrated array for that to hold up in court. I'm aware they have "exclude animal" but theres no way its at all accurate.
Using your mobile data and internet traffic is far easier and already deeply integrated into off the shelf law enforcement products. Those progams are even more terrifying than this by an order of magnitude.
Spot on, device tracking is much better than wifi sensing