London thugs will set up face recognition systems on streets, to check
the face of each person that passes by.
They say that each system will have a specific list of suspects' faces
to look for. However, today's face recognition systems are
inaccurate. If a suspect in the list is black, the system is likely
to trigger on other blacks who resemble the suspect. The thugs will
stop them and identify them, and determine that they are not that
suspect. This does not imply they will be allowed to proceed down
the street. They could be searched, arrested, whatever.
In effect, these systems can provide an excuse to stop large numbers
of people "for cause".
It doesn't go all the way to China, but it takes a big step in that
direction.