@randahl
> So every time a citizen turns on his phone, ... what he is doing online, and who he is talking to.
Every time a citizen does an on-line purchase their name and delivery address is made avaliable, every time a citizen enters range of a wifi-router whose owner did not care to end its SSID with "_nomap" suffix the oligoship knows where he is, regardless of the GPS being turned off. Usually, said citizen has also a home wifi routed through a telco operator on a long-term contract.
Long story short: one "turns out" their phone with every their move, and s/he is known the moment their device binded to the Google or Apple account.
The rest is taken care for by the dictatorship entities like RosKomNadozor in Russia, and Palantir in the U.S.
> the police writes down their phones' unique IMEI
A dissent prevention theater. The Roskomnadzor knows IMEI number at its first login to the GSM network, and knows who is using this device –by IMSI straight, or via the netlist built to date.
Average people do not know siloviki know. Hence they came with this "write-down" theater.
@briankrebs