Can Yard Signs Dictate the Scope of the Fourth Amendment?

by Matthew Tokson

In recent years, the Supreme Court has added a "trespass test" on top of the "reasonable expectation of privacy" test for Fourth Amendment searches. Under the trespass test, any government touching of "persons, houses, papers, [or] effects" for information-gathering purposes is a Fourth Amendment search.

This simple-sounding test, adopted in its modern form in 2012, has in short order produced several difficult questions for courts. In 2013's Florida v. Jardines, the Court's application of the test turned on a detailed analysis of the "background social norms" around approaching a house's front door. A divided Court ultimately concluded that these social norms prohibited the use of a drug-sniffing dog near the entryway of a house. Homeowners implicitly consent to police and other visitors approaching their door, knocking, and perhaps asking them questions or glancing around the doorway area--but owners do not implicitly consent to "canine forensic investigation." Accordingly, the police (and their dog) were physically touching the yard of a house without permission, which was a Fourth Amendment search requiring a warrant.

If a homeowner implicitly consents to police officers knocking on their doors, can they revoke that consent with a yard sign? 

This is not an abstract question; consent-revoking yard signs already exist.

It's a complicated issue, but the answer seems to be Yes. Although Jardines turned on the social norms surrounding house visits, it ultimately presented a question of property rights. In previous cases, the Court ruled that an implied license to visit a house can be withdrawn by "notice," such that subsequent approaches to the home are considered trespasses. In general (according to a leading property law scholar), state laws deem yard signs effective to revoke implied property licenses. 

Several courts have heard cases post-Jardines involving police officers ignoring a yard sign and approaching a house's front door, where they either discover something incriminating at the doorway or convince a resident to consent to police entry. These courts have held that a "No Trespassing" sign does not revoke the implied license allowing police officers to approach a door. But this is because of the banal content of the sign. Approaching a door is ordinarily not a trespass at all--so a sign reaffirming the legal prohibition on trespasses has no effect. The courts did confirm that a different sign would have a different effect, and that the key question was whether a reasonable person would interpret the sign as barring an approach to the door.  

It may be counterintuitive that yard signs could dictate the scope of the Fourth Amendment. Many No Soliciting signs are novelty signs meant both as a joke and as a genuine deterrent to uninvited visitors. It's easy to imagine a post-Jardines Fourth Amendment inquiry turning on whether a sign like the one below actually limits the homeowner's license to cookie sellers, or is only directed at non-cookie salespersons, or is too comical to give effective notice to a police officer not to approach a door.

It's also counterintuitive because observers have largely failed to appreciate how granular the Fourth Amendment has become under the physical intrusion test. Under the reasonable expectation of privacy test of United States v. Katz, the Court's determinations about societal expectations or social norms apply to all citizens, across the board. But under the trespass test, the Fourth Amendment is as individualized and locality-dependent as any set of property rights. One house with a certain yard sign may prohibit police knock-and-talks, while another with a similar sign may not. One town may establish a general license for drones flying over private property at a sufficient altitude, while another may prohibit flying drones over any private property without express permission. An apartment, condo, or house with a small yard may be lawfully sniff-able by drug-sniffing dogs, while a house set further back from the street would not be. The police may be prohibited from testing physical keys in locks, but permitted to test remote key fobs. There are also questions arising from things like easements. Can the police walk a drug-sniffing dog along an easement across your property with your neighbor's permission?

The majority of implied license cases will continue to be governed by general social norms and practices--which are themselves often problematic and difficult to ascertain. But a substantial subset of these cases will turn on more individual property characteristics, including the contents of yard signs

It's enough to make one miss the relative clarity and predictability of the Katz test.