&gt; The 4th amendment doesn&#x27;t say anything about &quot;private matters&quot;<p>The 4th amendment may not say that directly, but Chief Justice Roberts did in the majority opinion for Riley v. California:<p><pre><code>    Modern cell phones are not just another technological convenience.
    With all they contain and all they may reveal, they hold for many
    Americans “the privacies of life,” Boyd v. United States, 116 U.S., 630.
    The fact that technology now allows an individual to carry such
    information in his hand does not make the information any less worthy
    of the protection for which the Founders fought. Our answer to the
    question of what police must do before searching a cell phone seized
    incident to an arrest is accordingly simple—get a warrant.</code></pre>