If the police stop you, they may want to look at your cell phone. You probably take it with you everywhere you go and use it for far more than just making calls, meaning there is a lot of information about you on it.
So what is the situation with cell phones? Do you have to unlock them for the police if they ask after stopping you?
You have protection, but not as much as you might think
Back in 2014, in the case of Riley v. California, the Supreme Court ruled that the police generally need a warrant to search your phone. So if they stop you and ask you to unlock your phone, you can refuse (unless they do have a warrant).
Many people think this means they could then go and delete things from their phone that they don’t want the police to see, to ensure they are not still showing if the police reappear with a warrant. But it is not as simple as that.
There are records of your activity elsewhere
Deleting something from your phone does not mean it is gone for good. It means you have erased one copy of that information. The police can, and often do, subpoena companies that hold the other copies of that information.
For example, if they want to check your WhatsApp messages, they can subpoena Meta. If they want to check your search history, they can ask a court to subpoena Google, Firefox or Safari. And, if they want to check your whereabouts at a given time, they can subpoena your cell phone provider, Strava or any other company that tracked your location.
Remember that it is possible to face investigation or charges even if you did nothing wrong. If you ever have concerns about your cellphone data being used by the police against you, legal guidance may be wise.