The "big thinikers" in government sit around and try to dream up new ways to fight crime, or at least look like they are fighting crime. They don't need to produce results and can satisfy their political bosses and the public, who are spoon-fed through the media, with the perception that things are getting better. The brass in most police departments haven't been on the streets in many years, and have become seat polishers only concerned with career advancement. They will sign onto just about any program that comes down the pipe and try to take credit for thinking it up. Most street cops just want to get through their shift in one piece and go home. However, there are some eager beaver career builders who buy onto the programs and want to lead the charge. Again, it is all about career building and "ass kissing."
When a pair of uniform police officers knocks on your door in the night, they bank on the fact that most folks are intimidated by their presence and immediately become defensive. Most folks want to cooperate with the police and are eager to show they have nothing to hide. That is the psychology behind what is referred to as a "knock and talk." I've done them, and most cops have at one time or another. You have no probable cause to get a warrant for some activity you suspect is going on, so you knock on the door and try to talk the residents into a "consent" search. If the home owner refuses, the officers then begin asking what they have to hide, and if they have done noting wrong, they have nothing to worry about. It is a legitimate tactic, and in some cases, puts real scum-bags on notice that the cops are interested in them. This tactic was never intended to be used for fishing expeditions into law abiding people's lives for political reasons.
I was a police officer for 30 years. Like almost every cop, I worked the endless graveyard shifts, dealing with humanity when they are at their worse. I managed to work my way into detectives where I was able to remain until I retired. I'm not turning on my brothers & sisters in blue here, but there are rules of behavior and any shortcuts to those rules hurts us all. Just because a cop knocks on your door and asks for cooperation, does not mean you should give it. We have rights that protect us from unreasonable search and seizure. No one should give up their rights! Cops are taught how to talk people out of their rights, but we must remain firm. If an officer should tell you, "I could get a warrant." Tell them to go get one and close the door. Nobody HAS to talk to the police. It's an individual matter, but if an officer came to my home wanting to search for anything, I'd refuse. If my neighborhood officer wishes to talk about suspicious behavior in the neighborhood, I'll tell them what I know. Heck, if they want to use my living room for running a surveillance on a dope house down the street, I'll furnish the coffee and donuts. But I'm not going to gfive up any of my rights. Too many good men have died to secure them for me.