Re-running this post with a few minor updates. Contact tracing apps do not track surface or air contacts across time | Coldstreams Business and Tech
Bluetooth-based contact tracing apps are incapable of detecting close contacts across time.
Example: Someone sits on a bus or at a coffee shop seat, coughs, and then leaves, 30-60 seconds later a new person takes that seat, has direct contact with the seat, plus inhales the aerosolized viral particles and droplets expelled by the person who coughed. BLE-based phone apps are 100% incapable of detecting this close contact.