I read the security features for FaceID and the biggest issue I see for me is how it handles "changes to your face." It says if you change your face (shave thick beard off), FaceID will require a pin and then it will update your FaceID imprint. I often allow my family and friends to use my pin to get into my phone for various reasons. I've been begging for guest mode or multi-user support in iOS for many years, but I've at least always had an easy time either registering a new fingerprint for my wife or giving out my pin to people I trust. I wonder if I can register multiple faces, so my wife can access my phone. I wonder if someone is accessing my phone with my pin, if FaceID will then register that person's face and mine will no longer work until I login with my pin. I really wish TouchID was on the power button or back of the X, but since it's not there for backup when FaceID fails, I am trying to understand how FaceID will fit into my lifestyle. Does anyone else have others who access your phone? How would you want FaceID to handle multiple users?