For the last fucking time.
I posted this before, guess I'll post it again because it is useful and there is clarification on this matter:
NO, if you are simply arrested, they do NOT have the right to search your cell phone right away. They need a warrant to do this. In 2014, there were two cases that went to the Supreme Court that dealt with this very specific issue. In both Riley vs California and United States vs Wurie, the police arrested the defendants, and during a search incident to that arrest, the police seized each defendant's cell phone that was located on their person. Evidence of gang and weapons activity was discovered on Riley's phone, after police looked through text, photographs, and videos. In Wurie, police searched the defendant's phone finding he had received multiple calls from "my house. " They accessed the call log, traced it to the defendant's apartment, and then searched the apartment, finding drugs and firearms. Both defendants were convicted. The California Court of Appeals upheld Riley's conviction, but the First Circuit Court of Appeals overturned Wurie's conviction.
The USA Supreme Court heard both cases together, and in a 9-0 opinion, held that the police generally may not, without a warrant, search digital information on a cell phone seized from an individual who has been arrested. Just because they have the tools to do it, doesn't make it legal without a warrant.
Furthermore, last summer, the Supreme Court ruled that police must obtain a search warrant to access an individual's cellphone location information. They can't simply go to a cell phone provider and ask for tower data-they need a warrant. While that decision may limit the government's access to cellphone data, it has no impact on the ability of private companies to amass, use and sell their customers' information. That is because the Fourth Amendment only limits government conduct, not private conduct. Only Congress, in enacting legislation, can limit how private companies amass and use information.