Technological change is extremely rapid, often leaving the law (including legislators and judges) struggling to catch up. This divergence is evident with search and seizure issues, such as with cell phones.
Traditionally, the “search incident to arrest” exception to warrantless searches (which are generally unconstitutional) was based on the fear that arrestees may have concealed weapons, and/or may destroy pertinent evidence. In other words, because an arrestee may possess dangerous weapons or destroy evidence before a police officer can obtain it, warrantless searches of an arrestee’s person (including the area within his/her “immediate control”) were determined to be constitutional. (Chimel v. State of California (1969) 395 U.S. 752.)
Almost immediately, the doctrine from Chimel was tested. In United States v. Edwards,  the US Supreme Court seemingly reversed, or at least significantly modified, the ruling in Chimel. In Edwards, the Court held that a delayed search occurring ten hours after the actual arrest was nevertheless constitutional, because officers COULD have constitutionally conducted that same search during the arrest. Thus, the ten hour delay did not render that search unconstitutional. The Court seemed to move away from the two-prong test of Chimel (danger to the arresting officer or the fear of destroyed evidence).
In United States v. Robinson, a police officer searched the arrestee and found a small cigarette package containing heroin. The Court upheld this search, thus introducing the concept that “containers” found on an arrestee could be searched, incident to an arrest. The Court expressly noted that it was not following the Chimel doctrine, but was instead basing its reasoning on the notion that because an arrestee is legally in custody, his/her person (including containers) may be searched.
In 2011, in the case of People v. Diaz, the California Supreme Court held that cell phones, like cigarette packages, are “containers,” and thus police officers were “entitled to inspect” them (in Diaz, the cell phone search occurred at the police station, ninety minutes after the actual arrest).  Interestingly, the majority stated that everything “stored inside” the cell phone was considered “on the person” of the arrestee. Given the large storage capacities of cell phones, their increasing
capabilities and the introduction of “cloud” storage, this ruling seems extremely problematic.
The late Senator Ted Stevens once called the Internet a “series of tubes.” It seems likely that our legislators and judges will continue to struggle with the law and technological change.