The Importance of Privacy in Shared Spaces

By Rachel Lerner1

The Fourth Amendment right to be free from warrantless searches and seizures in one’s home is a deeply engrained constitutional protection.2 However, as the boundaries of what constitutes a “home” have become increasingly unclear in our urbanized world, the question has become: where do our constitutional boundaries start and where do they end? Does the Fourth Amendment’s protection extend to a shared apartment? A shared basement lounge? A shared hallway closet? How do we balance our core Fourth Amendment right to be protected in spaces “intimately linked” to our homes3 with the need to protect the public safety of an urbanized population who frequently use shared spaces?

This piece will argue that a locked storage unit shared between two cotenants in an apartment building deserves to have constitutional protection, under both a Dunn curtilage standard4 and a Katz reasonable expectation of privacy standard.5 Additionally, if the shared space is clearly demarcated between the two cotenants, law enforcement, even if granted entry into the storage unit by one consenting cotenant, must still seek a judicially approved warrant if they wish to search the entire storage unit. Otherwise, the search would be constitutionally invalid.

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Determining whether a search occurred under Fourth Amendment jurisprudence often proceeds along one of two main lines of reasoning. The first is based in property rights, especially in the home. The second inquires as to reasonable expectations of privacy.

First, the Supreme Court has said that the core of the Fourth Amendment is “the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion.”6 Constitutional jurisprudence defines the area “immediately surrounding and associated with the home” as “part of [the] home itself for Fourth Amendment purposes.”7 This area, defined as “curtilage,” is “intimately linked to the home, both physically and psychologically” and is, accordingly, where “privacy expectations are most heightened.”8

Whether an area is curtilage is heavily dependent upon the facts of the case. Specifically, United States v. Dunn established that courts should consider four factors: (1) “the proximity of the area claimed to be curtilage to the home,” (2) “whether the area is included within an enclosure surrounding the home,” (3) “the nature of the uses to which the area is put,” and (4) “the steps taken by the resident to protect the area from observation by people passing by.”9 As is often the case in making factual determinations, the Dunn court recognized that these factors must not be “mechanically applied,” but are “useful analytic tools” to test “whether the area in question is so intimately tied to the home itself that it should be placed under the home’s ‘umbrella’ of Fourth Amendment protection.”10

Even if an area is not curtilage within the meaning of Dunn, one may still have a reasonable expectation of privacy within the unit, despite its lack of connection to the home. The Supreme Court has held that “the Fourth Amendment protects people, not places” and has disavowed the premise that physical property boundaries control the right of the government to engage in a warrantless searches and seizures.11 Instead, the Court has built upon the traditional property-based curtilage understanding of the Fourth Amendment to extend constitutional protection to areas in which the defendant harbors a “reasonable expectation of privacy.”12 The “reasonable expectation” test, adopted by the Supreme Court in Katz, dictates that a court should determine, first, whether the defendant exhibited an actual expectation of privacy, and second, whether his expectation is one that society is prepared to recognize as reasonable.13

In analyzing whether one’s expectation of privacy is “reasonable,” the Supreme Court has considered a variety of factors, including “whether the party can exclude others from that place; whether the party took precautions to maintain the privacy; and whether the party had a key to the premises.”14 A cotenant who has taken substantial and extensive steps to exclude the public from her locked space and maintain her privacy can satisfy both the subjective and objective elements of the analysis under Katz.15 Simply by taking those steps, she manifests a subjective expectation of privacy, and an urban, space-constrained society should recognize that expectation as reasonable.

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A locked storage unit, though commonly shared in an urban setting, is a constitutionally protected area under the Fourth Amendment.

Following the property rationale of Dunn, the storage unit falls within the purview of “curtilage.” The only reasonable conclusion upon application of the four factors established by Dunn is that the Fourth Amendment protects a locked, shared storage unit. A locked, shared storage unit is typically proximately adjacent to one’s apartment, used as one would use a home, and is isolated from public view. As the Court noted in Jardines, “one virtue of the Fourth Amendment’s property-rights baseline is that it keeps easy cases easy.”16 That rationale should apply to a shared storage unit in an apartment building.

Following a privacy rationale under Katz, one who has exhibited an actual expectation of privacy­—such as by locking a storage unit and excluding another cotenant from accessing her belongings—and whose expectation society recognizes as reasonable may rely on the Fourth Amendment as protection against warrantless searches of a shared storage unit, even if that unit is outside the physical boundaries of one’s home. An urban, space-constrained society should recognize that expecting privacy in a locked and labeled storage unit is reasonable.17 Thus under Katz, law enforcement officers conduct a search subject to the Fourth Amendment whenever they enter such a space.

Furthermore, under either the “curtilage” standard or “reasonable expectation” test, the fact that one cotenant voluntarily opens the door to a shared storage unit at an officers’ request does not necessarily diminish another cotenant’s Fourth Amendment protection in that area.

Law enforcement may rely on an individual’s consent to a search only if that individual is authorized to give consent and consents voluntarily.18 In shared spaces, consent by third parties is valid only when the police can reasonably believe the consenting party possesses common authority over the entirety of the shared space.19 The touchstone of this reasonableness inquiry requires looking at the particular facts concerning a specific shared space and assessing the “social expectations” the parties of the shared space may hold.20 If there is no reasonable belief in common authority over a shared storage unit, there is no valid consent to a search of the entire storage unit.21

Therefore, one cotenant does not always have authority to consent to a search of the other cotenant’s items.22 For example, if a “Neighbor Agreement” is posted on the door of the storage unit, which makes it clear that one cotenant is forbidden to touch or move any of the other cotenant’s belongings, it would be unreasonable for officers to conclude that one cotenant could consent to a search of the other’s belongings. Additionally, if areas are clearly demarcated, consent to one area does not reasonably extend to consent for all areas. 23

Additionally, Justice Scalia’s reasoning regarding Fourth Amendment protections in Florida v. Jardines also illustrates the limits to a cotenant’s consent. Even though a cotenant might voluntarily open the door to the locked storage unit for officers, “[t]he scope of a license – express or implied – is limited not only to a particular area but also to a specific purpose.”24 Background social norms and the unique circumstances of the consent will affect this analysis. For example, while finding “a visitor knocking on the door is routine” for some, spotting “th[at] same visitor exploring the front path with a metal detector . . . would inspire most of us to – well, call the police.”25 Therefore, if the officers approached a cotenant, sought consent to enter a storage unit, and announced their purpose was to speak to her about the other cotenant, without explicitly or implicitly telling her that they intended to search the other cotenant’s items, the consent to enter the unit does not reasonably extend to searching the entire unit beyond the consenting cotenant’s items.

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In sum, a shared, locked storage unit enjoys constitutional protection under the Fourth Amendment, both under the Dunn curtilage standard and the Katz “reasonable expectations” test. Additionally, one cotenant cannot always give reasonable consent to a search of the entire unit, especially when areas are clearly demarcated or detailed through a posted “Cotenant Agreement.” Therefore, searching such a space requires probable cause and a warrant.


1. Rachel Lerner is a 3L at New York University School of Law. This piece is a commentary on the 2017 Evan A. Evans Constitutional Law Moot Court Competition hosted by the University of Wisconsin Moot Court Board. The views expressed in this article do not necessarily represent the views of the author on this point of law. Rather, this article is a distillation of one side of an argument assigned to the author at the 2017 Evan A. Evans Constitutional Law Moot Court Competition. For another commentary from this competition, see  Search, Seizure, and the Smartphone: Rethinking Privacy Protections in the Digital Age.
2. See Payton v. New York, 445 U.S. 573, 586 (1980) (“It is a ‘basic principle of Fourth Amendment law’ that searches and seizures inside a home without a warrant are presumptively unreasonable.” (footnote omitted)).
3. See Florida v. Jardines, 569 U.S. 1, 6-7 (“the area ‘immediately surrounding and associated with the home’ . . . is ‘intimately linked to the home’” and thus warrants Fourth Amendment protection).
4. See United States v. Dunn, 480 U.S. 294, 301 (1987) (establishing that whether an area is constitutionally protected curtilage is heavily dependent on the facts).
5. See Katz v. United States, 389 U.S. 347, 351 (1967) (holding that constitutional protection extends to areas outside the home in which people harbor reasonable expectations of privacy).
6. Silverman v. United States, 365 U.S. 505, 511 (1961).
7. Oliver v. United States, 466 U.S. 170, 180 (1984).
8. California v. Ciraolo, 476 U.S. 207, 213 (1986).
9. United States v. Dunn, 480 U.S. 294, 301 (1987); see also L.A. Police Protective League v. Gates, 907 F.2d 879, 885 (9th Cir. 1990) (relying on the Dunn test to find an area was constitutionally protected curtilage); United States v. Mooring, 137 F.3d 595, 596-97 (8th Cir. 1998) (same).
10. Dunn, 480 U.S. at 301.
11. Katz v. United States, 389 U.S. 347, 351 (1967).
12. Florida v. Jardines, 133 S. Ct. 1409, 1417 (2013) (holding that Fourth Amendment protections extends outside the boundaries of one’s home and property); see also United States v. Hoffman, 677 F. Supp. 589, 596 (E.D. Wis. 1998) (“[A] person can have a protected expectation of privacy in buildings . . . that are located far outside the area of the curtilage of the home.”).
13. See Smith v. Maryland, 442 U.S. 735, 740 (1979) (citing Katz, 389 U.S. at 351, 361).
14. United States v. McCaster, 193 F.3d 930, 933 (citing Rawlings v. Kentucky, 448 U.S. 98, 105 (1980)).
15. See United States v. Santa Maria, 15 F.3d 879, 883 (9th Cir. 1994) (finding that the defendant had a reasonable expectation of privacy in a locked unit in which he kept his tools).
16. Jardines, 133 S. Ct. at 1417.
17. See McCaster, 193 F.3d at 933; Santa Maria, 15 F.3d at 883 (finding that locked and private spaces are protected under the Katz reasonableness test).
18. See United States v. Matlock, 415 U.S. 164, 171 (1974).
19. See Illinois v. Rodriguez, 497 U.S. 177, 179 (1990) (holding that a search of an entire shared apartment was constitutional after the consenting renter referred to it as “our” apartment, and said that she had clothes and furniture inside).
20. See Georgia v. Randolph, 547 U.S. 103, 111 (2006) (“The constant element in assessing Fourth Amendment reasonableness in consent cases … is the great significance given to widely shared social expectations, which are naturally enough influenced by the law of property, but are not controlled by its rules).
21. See Matlock, 415 U.S. at 170.
22. See United States v. Amratiel, 622 F.3d 914, 915 (8th Cir. 2010) (holding that consent by a third party is valid only if an officer can “reasonably rel[y] on a third party’s demonstration of apparent authority” over the property being searched).
23. Cf. United States v. Penaloza-Romero, No. CRIM. 13-36 RHK/TNL, 2013 WL 5472283, at *7 (D. Minn. Sept. 30, 2013) (holding that officers had a right to search a common hallway of a building under the expressly granted authority of the complex manager).
24. Jardines, 133 S. Ct. at 1416.
25. Id.