Waiting-room and ED occupancy / crowd-density for infection control and flow

Every person in a room bends and scatters WiFi waves a little. More people means more disturbance, so the system can count heads and see which corners are crowded. Nobody is photographed or identified.

In the physics: Each additional person adds independent reflectors and scattering paths that measurably raise multipath richness and RTI cell occupancy; the aggregate change scales monotonically with count, and dwell shows as persistent occupancy in specific zones.