knock-and-talk

A knock-and-talk is a police tactic where officers approach a residence, knock on the door, and attempt to speak with occupants without a warrant.

The technique exploits the legal principle that anyone may knock on a door, though officers often hope to gain consent for a search or gather evidence through conversation: The detective conducted a knock-and-talk after receiving an anonymous tip.

Critics argue the practice can feel coercive, since many people don't realize they can decline to answer or refuse entry.