Reasonable Expectation of Privacy (2024)

Reasonable Expectation of Privacy

The Fourth Amendment tothe United States Constitution guarantees that people will be safe fromunreasonable searches and seizures.[1] In the Supreme Court case, Katz v United States,[2] the Court developedthe idea of a “reasonable expectation of privacy.” The Katz case dealt with a wiretap on apublic phone booth as police attempted to thwart a gambling ring. The Court stated that there was anexpectation of privacy in a phone conversation, even if that conversation tookplace in a public phone booth.

The Court also ruled,though, that anything that a person knowingly exposes to the public, regardlessof location, is not protected by the Fourth Amendment. A person must keep something private for theFourth Amendment to apply.

To determine whetherthere exists a “reasonable expectation of privacy,” a two-prong test has beenestablished.

First, the person mustshow a “subjective” expectation that his activities or items would be private.

Second, the individualmust show that his subjective expectation of privacy is one which societyconsiders reasonable.[3]

To illustrate how thistest works, let’s consider cases in which there is and is not a reasonableexpectation of privacy.

People have reasonableexpectations of privacy in their own person, house, vehicles, and businessoffices. They also have a reasonable expectation of privacy in their personalcommunications such as telephone calls, letters, and journals. Moreover, if a person needs a key or passwordto gain entry into a space, whether they are physical or electronic, there isalso an expectation of privacy in that space. Examples here include cellphones, computers, bank safety deposit boxes, lockers, and luggage.

In contrast, people haveno reasonable expectation of privacy in public spaces where their actions, possessions can be seen or conversations heard, again whether thecontent at issue is physical or virtual.Some examples of such places are public sidewalks, venues hosting sportingevents and public parks. There is no reasonable expectation of privacy in discardedgarbage left in the street. Electronically,there is also no reasonable expectation of privacy in phone numbers dialed, inthe GPS location of a vehicle, electronic bank records, communications via theInternet, including e-mail, chat room or social media, in files accessiblethrough file sharing software, in information provided by customers to Internetproviders, including identifying address information.[4]

A person also has noreasonable expectation of privacy in odors emanating from one’s person orluggage. This is why, for example, a police officer who smells alcohol on adriver’s breath may use that fact as evidence against the driver. In fact, a2005 United States Supreme Court decision ruled that police dogs trained tosniff narcotics that indicate the presence of narcotics in a car could providethe probable cause necessary to allow police to search the vehicle.[5]

Furthermore, apassenger in a car has no reasonable expectation of privacy in the contents ofthat car.[6] So, for example, if avehicle’s driver consents to the search of a car, materials found in the carthat belong to a passenger can be used against that passenger. The driver, onthe other hand, does have a reasonable expectation of privacy in the contentsof the vehicle and thus can refuse police permission to search the vehicle(unless the police otherwise have a legal right to search it).

By the same token,while a homeowner (or renter) has a reasonable expectation of privacy in thecontents of the home, a guest in a house has no reasonable expectation ofprivacy in that house.[7] If the home owner consents to allow police tosearch a house, the possessions of the guests in that house are fair game.

Even in places and initems where there is generally a reasonable expectation of privacy, exceptionsexist. For example, even within one’shome or property, the “open-field” doctrine provides that if something on aperson’s property is easily visible to the public without the need to be physicallyon the property (e.g., from the air from the street) then there is noexpectation of privacy. For example, thepolice can use photos taken by police helicopters above one’s property of itemsthat are visible from the air.

The expectation ofprivacy is reduced for people who are public employees. Employees who holdsafety or security sensitive jobs such as bus drivers, train conductors, lawenforcement officers or laboratory workers, have reducedexpectations of privacy. Because of the trust society is putting in theseindividuals, that compelling state interest overrides the individual’sexpectation of privacy. These peoplemay, for example, be subjected to drug testing that the government could notsubject an ordinary person to. [8]

Moreover, when peoplevoluntarily enter space in which the government has an elevated securityinterest, the expectation of privacy is likewise reduced. The most obviousexample occurs at airports. Transportation Security Administration agents maysubject airline passengers and their luggage to virtually unlimited searchingwith virtually no cause, which would never be allowed in most other contexts.

Rules relating to thedoctrine of expectation of privacy do not operate within a vacuum. Reasonableexpectations of reasonable people, factors including location, nature of theobjects or data and many other factors must be considered. As such, whether areasonable expectation of privacy exists is a matter that is determined on acase by case basis, and is fact-specific.