living inside THAT universe, some of that is answered, also some with narration: first, the whole premise is about HOW these people are NOT getting found and arrested. assuming (since they don't tell us) their communications from their inbuilt whatever CAN have glitches - like our cell phones - sometimes you DON'T get the insta-feed about who everyone is. System SEES someone, but gets no info from the google database so it tosses up error. Maybe happens randomly and often enough and after so so many false arrests due to a temp communication hiccup, the police have ceased nabbing everyone that has a temp gitch.
If she were followed, she'd know it from the feeds she intercepts - probably an alert system coded into hers (shes a hacker) and she'd launch a false live video feed and dissapear anyway.
There weren't other cops - they covered this in the dialogging - because she would notice the streams/broadcasts from them and stay away.
She'd erase any surveillance cameras in the vicinity.
The whole film is about the power she had over this system. I felt most of that was pretty tidy, but yes, it is just a movie and full of holes. One solution would have been physical: while standing close, snap hand cuffs on her to himself. BOOM! No amount of hacking would change that. Unless she HACKED her arm off with an axe. :D
I'm not defending the film really, but stretched like this, "IN TIME", even "GATTACA" require some leeway to entertain. :0