New tech uses Wi-Fi to count people through walls

Whether you’re trying to figure out how many students are attending your lectures or how many evil aliens have taken your Space Force brethren hostage, Wi-Fi can now be used to count them all.
The system, created by researchers at UC Santa Barbara, uses a single Wi-Fi router outside of the room to measure attenuation and signal drops. From the release:
The transmitter sends a wireless signal whose received signal strength (RSSI) is measured by the receiver. Using only such received signal