Malls and stores have done this for a decade and then some, from devices on you.
Friendly reminder many manufactured goods also have RFID stickers within, used to track/trace parts during factory assembly. These are active and readable at all times by systems like this - irrespective of if the devices are powered.
mirror: https://tech.yahoo.com/cybersecurity/articles/flock-style-sc...
we have reached the point where now at any point in the future they can trace anyone backwards for months without a warrant (and without probable cause)
they can pick a person and then just look for a crime to prosecute since most people break laws daily without realizing it
Torment Nexus looms ever closer.