BlueProximity is a cool GNOME application that detects the proximity to a Bluetooth device to determine whether the user is in proximity. If the user is way the screen will be locked (or any command be run), when the user is in proximity the screen will be unlocked (or any command be run).
However if the screen is manually locked it will not be unlocked because the Bluetooth device is in proximity. Should the screen be locked because the Bluetooth device is away, you can manually unlock the screen.
Blueproximity allows you to secure your machine while not going through the inconvenience of locking the screen when you are leaving the machine and then unlocking it when you are back. BlueProximity, Leave it - it’s locked, come back - it’s back too…