Scientists in Germany have demonstrated a startling new form of surveillance: identifying people using nothing more than ordinary WiFi signals. By analyzing how radio waves bounce around a room, researchers can effectively “see” and recognize individuals — even if they are not carrying a device and even if their phone is turned off.
The AP is what does the tracking. If you build your own, and only you can access it, then it can’t watch you. VPNs don’t solve any of this, it’s not about a device being encrypted or not.