Ever since Apple did it, everyone jumped on the “Face Unlock” bandwagon. Except, unlike Apple, most just rely on the selfie camera and no additional hardware for a proper biometric authentication. And that just doesn't offer the same level of security.
@rik demonstrated that a OnePlus 6 will happily unlock with just a photograph of a face. Even a black & white photo worked! The phone was trained on Rik’s face.
Well, there’s a reason that Apple jammed an entire Kinect in the iPhone X. And why Samsung and a few others use iris scanners. If you need a secure way to lock your OnePlus 6, stick with the fingerprint reader.
Strangely, the OnePlus 5T doesn’t seem to be fooled by photos, whether printed or on a digital screen.