Behold, the first prototype of my amazing new invention: The reverse one-way screw! The natural counterpart to those anti-theft screws used to attach license plates to cars, the ROWS can only ever be unscrewed, not driven in.
To use it, simply already have it installed somewhere, and unscrew it like you would a regular screw - attempts to reinstall it will simply result in the screwdriver safely slipping out of the head, with no risk of it actually being driven back in.
A higher angle photo of the screw, better showing the geometry of the head. It can only be turned anti-clockwise, which would unscrew the screw; attempting to turn it clockwise to drive the screw into something will result in the screwdriver slipping off the sloped surfaces instead.
A photo of an enlarged, 3D printed machine screw in matte grey. The thread is about 2cm wide, the screw itself 5cm tall, and with an unusual head with two features - each has a flat wall and a smooth sloped one. It's a one-way screw, designed so it can be driven only in one direction.