It’s an exaggeration. But, in many cases, the police are not required to tell you the truth, and are often trying to see if you are committing a crime without admitting that this is what they are doing. Or, they are investigating a possible crime without telling you that this is what they are doing. It isn’t actually their job to prevent crime. It is to catch and arrest criminals.

I’ll give an anecdotal, example. Police came to my door looking for an ex roommate for tax evasion. Rather than ask me if he was there, the officer deliberately mispronounced the name…so that I would correct him in then pronunciation. In this way, I admit to knowing the the roommate. Not sure why he tricked me this way, but he did. The bastard.