Notwithstanding an unlawful, forcible police entry into his residence, Artic voluntarily consented to the subsequent search of the house, which was also sufficiently attenuated from the illegal entry to purge the taint of the illegal entry.
The police clearly had probable cause to get a search warrant — they had just established that Artic’s (the owner) son had retrieved cocaine from within. But before getting the warrant, they decided to perform a “knock and talk.” No one answered, so one of the detectives went around to the back to make sure no one got away; that was the first illegal act, because the back was fenced off. She reported movements inside the house to the officers in front and they kicked in the outer front door. Then they broke into the inner front door. If you’re keeping score at home, that’s three illegal acts. One detective went up to the second floor, gun drawn, knocked on a closed door, “asked” if he could come in, and Wagner said, yes. Within the next five minutes, Artic “consented” to a full search of the house, which the court upholds notwithstanding the illegal entry. The facts won’t be further recited here. Search and seizure cases are necessarily fact-intensive, making generalizations about any given case unproductive. But it’s fair to discern in this case a trend that bids to take the label attached to mundane police activity — “knock and talk” — and turn it into a veritable exception to the warrant requirement.
Get the supposedly larger principles out the way, voluntary consent and taint-attenuation. “To determine if the consent exception is satisfied, we review, first, whether consent was given in fact by words, gestures, or conduct; and, second, whether the consent given was voluntary,” ¶30. Compare the majority’s analysis (¶¶30-62) to the dissent’s (¶¶111-21), and draw your own conclusion. Attenuation is a 3-factor test: temporal proximity of consent to primary illegality, intervening circumstances, purpose and flagrancy of misconduct, ¶66. Police just bulled their way into your home? No problem. What follows is perfectly “congenial,” so of course your happily-given permission to turn your house upside down is severed from any misunderstanding caused by the entry. Ultimately, you’ll again have to see for yourself, comparing majority (¶¶63-105) to dissent’s (¶¶128-47) analysis. The majority’s final thought is worth quoting, though, as it captures much of the flavor of its analysis:
¶105 While the officers here did break down the front doors to the building, there is nothing in the record to suggest that their actions were calculated to surprise, frighten, or confuse Artic, whom they did not realize was an occupant of the house. The officers were furthering a legitimate law enforcement purpose, see Scheets, 188 F.3d at 840, acting on a reasonable belief that evidence might be destroyed, and not specifically targeting Artic. In sum, the record simply does not suggest “bad faith exploitation of the situation on the part of the officer[s].” Richter, 235 Wis. 2d 524, ¶53. Therefore, their actions were neither purposeful nor flagrant, and this factor weighs in favor of attenuation.
Well, they may not have known that Artic was an occupant, but so what? They knew someone was inside, in fact that’s the very reason they went. Not only that, but the entire basis for the (unlawful) entry was to prevent destruction of contraband by whomever it was, ¶26 (“the officers acted upon their belief that evidence was being destroyed”). Which means, they very much wanted “to surprise, frighten, or confuse” whomever was inside, otherwise, what’s the point of smashing their way in?
But the real star of the show is the “knock and talk” technique. It’s ill-defined (see, for example, State v. Robinson, 2010 WI 80, ¶7 n. 5). But that’s because it just means that the police go up to a house to knock on the door and see what happens. The public has an “implied invitation” to walk up up to someone’s front door and knock. Whether limits should be imposed on police authority to do it is an on-going dispute, but merely calling the technique “knock and talk” doesn’t expand police authority to intrude on residential privacy interests. And yet the court apparently sees it otherwise, indeed is well on its way to elevating “knock and talk” into its own exception to the warrant requirement. Remember that illegal entry into Artic’s back yard? Well, maybe it wasn’t really that unlawful after all:
¶95 Nevertheless, we recognize that officers may sometimes enter curtilage to further a “legitimate law enforcement objective” when the restriction upon a person’s privacy is limited. … Some courts have also defined an exception permitting officers to enter the curtilage when engaging in a “knock and talk” investigation. See Hardesty v. Hamburg Twp., 416 [sic, 461] F.3d 646, 654 (6th Cir. 2006); see also United States v. Troop, 514 F.3d 405, 410 (5th Cir. 2008) (holding that a “knock and talk” is a “reasonable investigative tool when officers seek to gain an occupant’s consent to search or when officers reasonably suspect criminal activity”). Several courts have extended this exception to permit officers to enter the back yard in search of a homeowner when nobody answers the front door.
It is not quite as simple as, “an exception permitting officers to enter the curtilage when engaging in a ‘knock and talk.'” Troop, for example, says:
The Government asserts that the agents were attempting a “knock and talk” strategy that is permitted under Fifth Circuit precedent. It is true that our precedent holds that the knock and talk strategy is a “reasonable investigative tool when officers seek to gain an occupant’s consent to search or when officers reasonably suspect criminal activity.” Jones, 239 F.3d at 720. However, we have also held that when no one answers the door, the officers should end the knock and talk and “change[ their strategy by retreating cautiously, seeking a search warrant, or conducting further surveillance.” Gomez-Moreno, 479 F.3d at 356. In the instant case, rather then changing their strategy when no one responded to the knocks on the door, the agents proceeded `to conduct a warrantless search of the curtilage of Troop’s house, going so far as to reach inside the window and grab an occupant.  Gomez-Moreno counsels us that such conduct is not permitted under the Fourth Amendment.
Familiar refrain: read the cases cited by Artic (fn. 15) and draw your own conclusions. It is highly likely that the police will take opinions such as this one as an implied invitation to stretch the “knock and talk” doctrine as far as possible. You will have to be prepared to litigate the doctrine on the law and the particular facts. You have an ever-expanding body of caselaw to assist (and limit) you. The merest smattering may be found here and here (scrolling down a bit in each instance).
All that said, note that the court readily assumed without real analysis that the police presence in the back yard was unlawful (¶26). If the idea is that the house needed to be secured so that obtaining a warrant would be productive, then finding justification for the police presence in the back yard would further the policy favoring the warrant requirement. How else could they fully secure the premises without warrantless intrusion? A holding to that effect would have been narrower than those the court adopted — and that, among other things, is the point.