Michigan v. Frederick

Issue: (1) Whether the Fourth Amendment applies to knock-and-talk encounters; (2) whether, if it does, the Michigan Supreme Court correctly held that a predawn visit constitutes a constitutional trespass in violation of the implied license to approach; and (3) whether, if it does, the Michigan Supreme Court correctly held that "any attempt to gather information," including simply asking the occupants for consent to search, combined with a constitutional trespass, constitutes a search under the Fourth Amendment.