Knock and talk is a law enforcement tactic employed by police to make legitimate inquiries about alleged criminal activities by knocking on people's doors and talking to them about the allegations. The procedure is ostensibly one of information seeking. Knock and talk requires balancing the intrusion of protected interests under the Fourth Amendment with the promotion of legitimate governmental interests, including those of police officer safety.
The following is an example of a caselaw on knock and talk:
A ‘knock and talk’ encounter is a procedure ordinarily used by police officers to investigate a complaint where there is no probable cause for a search warrant. In employing this procedure, police officers knock on the door, try to make contact with persons inside, and talk to them about the subject of the complaints underlying the investigation. Such a consensual encounter may lead to a request by the police for voluntary consent to conduct a search. Courts generally have upheld the knock-and-talk investigative procedure as a legitimate effort to obtain a suspect's consent to search. The key to the legitimacy of the knock-and-talk technique--as well as any other technique employed to obtain consent to search--is the absence of coercive police conduct, including any express or implied assertion of authority to enter or authority to search. In properly initiating a knock-and-talk encounter, the police should not deploy overbearing tactics that essentially force the individual out of the home. Nor should overbearing tactics be employed in gaining entry to a dwelling or in obtaining consent to search. [Luna-Martinez v. State, 984 So. 2d 592 (Fla. Dist. Ct. App. 2d Dist. 2008]
Knock and talk is also known as rap and tap.