Google's smart doorbell system, Nest Hello, has one feature which automatically locks the door if it doesn't recognize the face on the other side.
This is a pretty remarkable safety feature to have and it likely gives residents inside the home a sense of comfort, knowing their doorbell system is watching out for them.
However, that doesn't mean the Nest's facial recognition software can't make a few mistakes here and there. No one's perfect guys, not even doorbells.