If I do not password protect my phone, do I forfeit reasonable expectation of privacy?
<p>Let's say I am arrested and I have a smartphone in my possession. A police officer cannot, without a warrant, seize my phone, unlock it and go through my pictures, messages, etc. The US Supreme Court unanimously concurred in <em>Riley v. California</em>. In such a case, a person who locks his phone is asserting a reasonable expectation of privacy and the 4th Amendment protects said person.</p>

<p>Now let’s say I am arrested and I have a non-password-protected smartphone in my possession. The phone is completely unlocked. By simply not setting a password or other “lock screen,” have I inadvertently waived my expectation of privacy?</p>

<p>The closest court case I’ve found is US Court of Appeals 6th circuit <em>Huff v Spaw</em>. The phone owner accidentally pocket-dialed another person. The court held (to paraphrase) that while the phone owner <strong>assumed</strong> an expectation of privacy, he did not <strong>exhibit</strong> the expectation of privacy because he did not take precautions to prevent pocket-dialing.</p>

<p>Without a warrant, the police cannot enter your house, even if your closed front door is unlocked. But phones are not houses and the expectation of privacy is different. I’m wondering if there are any court cases, laws, etc. that confirm or deny that I have (or don’t have) a reasonable expectation of privacy if I choose to not password-protect my smartphone.</p>

<p>I'm not aware of case law on point, other than <a href="https://www.oyez.org/cases/2013/13-132" rel="noreferrer"><em>Riley</em></a>, which you mention (which doesn't mean that there isn't any - I'm not a specialist in this area). </p>

<p>But, I think that the answer would be that you do have an expectation of privacy because the <em>Riley</em> holding that there was an expectation of privacy in a smart phone didn't really hinge in any meaningful way on the existence of a password. The linked summary of the Riley decision explains the court's reasoning as follows:</p>

<blockquote>
  <p>Chief Justice John G. Roberts, Jr. wrote the opinion for the
  unanimous Court. The Court held that the warrantless search exception
  following an arrest exists for the purposes of protecting officer
  safety and preserving evidence, neither of which is at issue in the
  search of digital data. The digital data cannot be used as a weapon to
  harm an arresting officer, and police officers have the ability to
  preserve evidence while awaiting a warrant by disconnecting the phone
  from the network and placing the phone in a "Faraday bag." The Court
  characterized cell phones as minicomputers filled with massive amounts
  of private information, which distinguished them from the traditional
  items that can be seized from an arrestee's person, such as a wallet.
  The Court also held that information accessible via the phone but
  stored using "cloud computing" is not even "on the arrestee's person."
  Nonetheless, the Court held that some warrantless searches of cell
  phones might be permitted in an emergency: when the government's
  interests are so compelling that a search would be reasonable.</p>
  
  <p>Justice Samuel A. Alito, Jr. wrote an opinion concurring in part and
  concurring in the judgment in which he expressed doubt that the
  warrantless search exception following an arrest exists for the sole
  or primary purposes of protecting officer safety and preserving
  evidence. In light of the privacy interests at stake, however, he
  agreed that the majority's conclusion was the best solution. Justice
  Alito also suggested that the legislature enact laws that draw
  reasonable distinctions regarding when and what information within a
  phone can be reasonably searched following an arrest.</p>
</blockquote>

<p>The 4th Amendment expressly protects "papers" in your possession, which can't be password protected, and a smart phone file is analogous to a "paper" for 4th Amendment purposes. Your expectation of privacy in an unlocked smart phone flows from your exclusive possession of the phone as a piece of tangible personal property containing information, and not just from the password protection. In the same vein, I don't think that you would need to have a lock on a diary to have an expectation of privacy in it.</p>

<p>This said, this is a cutting edge area of the law and password protection for a smart phone provides both more practical protection and potentially a less ambiguous cases of legal protection from search (since it brings you closer to the facts of <em>Riley</em>), and is therefore still a good idea.</p>

united-states criminal-law privacy search-and-seizure fourth-amendment