what I noticed in iv was that while hiding; meaning behind an object that completely covers your body and head, police would not notice you, now if you came in the radius of detection which is circular and not at a fixed angle, you would be detected. So while you where behind cover, and logically there was literally no way for police to see you, they wouldn't but if one bit of your body came in contact with their 360 radius of sight, then you would be chased after, this can be most observed by looking at the stars on top.
hopefully these mechanics will improve in v, to a more realistic scenario where there is a fixed angle on the head of the AI, which will include direction of head. then it wouldn't be as fucked up as getting a wanted star for aiming your gun at a policeman who isn't even facing the gun.