Every cop you walk by is already recording you, in a forgetful, hostile, and potentially hallucinatory medium.
This sort of tracking can and is already be done manually in relatively small areas using CCTV footage (airports, malls, hotels), but expect to see it become "a thing" for entire cities. "Quantity has a quality all its own."
http://en.wikipedia.org/wiki/Assassination_of_Mahmoud_Al-Mab...
"The chief of Dubai Police Dhahi Khalfan Tamim said that there are 648 hours of video films in which the 27 suspected persons are appearing.[110]"
I'm not a big fan of surveillance, but it seems to me that being able to retroactively follow individuals throughout the city could be a good tradeoff if it means the police can never again send an innocent person to prison by planting drugs on him after arresting him for something he didn't even do.
The problem is having a huge pile of incomplete evidence makes it easier to make up violations and get them to stick.
Illegitimate prosecutions are built on confirmation bias. The amount of false positive evidence against you is proportional to the amount of surveillance you're under. More government cameras only produce more false positive evidence against you. Meanwhile government cameras can't really help you because your public defender doesn't have the resources to look through the footage and regardless any strong evidence of your innocence will have been the victim of a camera malfunction which "isn't suspicious" because it "happens all the time."
The better solution is for citizens to carry cameras and to have strong laws protecting the right of citizens to record the police. That way the footage can't "disappear" as easily and the recordings are decentralized so you aren't making it easier to fabricate an illegitimate prosecution out of the biased selection of false positives from big data.