Also, mass tracking through mobile devices. Even if said devices are in faraday cages, it doesn't take a genius to see that something exists in some area when t

Also, mass tracking through mobile devices. Even if said devices are in faraday cages, it doesn't take a genius to see that something exists in some area when there are many devices going dark and then coming back up again after some hours. It only takes access to cellphone towers and data.