The question of whether cops can force someone to unlock their phone in the US for a search hinges on Fifth Amendment protections against self-incrimination—that no one “shall be compelled in any criminal case to be a witness against” themselves. Privacy advocates argue that this extends to the act of unlocking a phone or generally decrypting data on a device. But while that line of thinking has succeeded as a defense against having to produce a passcode, it works less reliably in the context of Touch ID or other biometrics. Something you know, like a passcode, is easier to view as testimonial—legally speaking, a statement made by a witness—than something you have, like a physical attribute.
“Big picture, a warrant is required for the search of a device except in certain circumstances at the border,” says Greg Nojeim, director of the Freedom, Security and Technology Project at the Center for Democracy & Technology. In the newly reported Face ID case, police did have a warrant to compel 28-year-old Grant Michalski of Ohio to unlock his smartphone, and Michalski has gone on to face child pornography charges.
You can manually disable Face ID by holding the Side Button (Sleep/Wake) and Volume Up Button together to bring up the “Slide to Power Off, Emergency Medical ID, and Emergency SOS” screen. Simply tap “Cancel”. Your iPhone is now locked and Face ID is disabled.
Good to know.