[rtkwe]

It's the accumulation and correlation of the data that's the problem. At a high enough density you essentially have everyone being followed their entire lives. Formerly if the police wanted to know everywhere that a person visited because they suspected them of crime X they'd have to invest a certain level of resources which means targets had to be chosen judiciously. Now we're approaching a point where they can just trawl everyone's movements looking for anything they like, and as the algorithms get better and the density of things like CCTV and the license plate readers increases it gets easier and easier to follow anyone back in time.

IF the police were filled with perfect angels and laws were all perfectly reasonable and just allowing that might approach being ok. Instead we have a police force made of people who do things like harass whistle blowers who reveal corruption or cover ups or people they have personal vendettas against (or unrequited love toward).