I don't want my ISP doing this to me, but it sounds like something pretty cool to do myself. Does anybody know what the current state of "self-hosting" this kind of functionality is?
I am also super interested for the personal use case. What is the resolution? Can I track my cat through the house? See when they go to the feeder? Count my own bathroom visits?
Just get cameras and local storage/processing for them. No need for elaborate Wi-Fi presence detection hacks.
Check out ESP32-based projects like ESP32-CSI-Tool or the FreqSense library, which can implement WiFi sensing with minimal hardware and completely under your control.