You are confused
It doesn't work but the cops are too fascinated with their new shiny-shiny to care.
Also it's helpfully biased towards the same certain segments of the population they are, so helps them play "stop and search snooker".
Let's not forget the average plod barely knows the laws they have to enforce on a daily basis* let alone data privacy ones.
*Like the poor sod they arrested for walking past the camera vans in Wales with his face covered, which is not actually illegal.
Biting the hand that feeds IT
