People usually sleep near their phones. Couldn't someone just use your hand while you're asleep to unlock your phone? They should add some features that prevent this. Like, your face has to be recognized by iSight camera with your eyes open also. Or, you can set fingerprint unlock to require a passcode between the hours of X and Y, or whenever you have Do Not Disturb activated. Obviously you could restart your phone every night before bed then lock it, but that seems draconian.