The concept was proposed as a design idea to help reduce the incidence of “dooring” injuries to cyclists: https://safedesign.wordpress.com/2012/05/24/cycling-dooring-hazard-design-is-the-solution-not-penalties/
Taking the design concept further:
Ideally the warning needs to occur a second or two before the door opens. Thinking about driver behaviour and routines: a car driver parks a car and would typically turn off the engine and remove the key (most cars have a key) before opening the door. Perhaps then the anti-dooring signal could initiate with the removal of the key, remain on while the door is open and deactivate when it is closed. A timeout could also be a feature for those cases where people park a car and want to leave the door open (e.g. in their yard, when working on the car, etc).