I phone safety

Do you often hand them your device when locked? Are they a family member? A child?

the odds of any random person in the public being able to unlock your device is very small, around 1 in a million.

why can my sister unlock my phone with fa… - Apple Community

About Face ID advanced technology - Apple Support

Change your passcode and don’t share it.

Reset your FaceID; installing only your face.

Then see if this “2nd person” can still unlock your phone.

Don’t share your unlocked phone.