They either built some smarts into the sensor, where it's physically impossible to trick it or you can just pretend to be a sensor capturing whatever you want.

They either built some smarts into the sensor, where it's physically impossible to trick it or you can just pretend to be a sensor capturing whatever you want. I assume with enough desire, you can built a pixel-for-pixel matching LCD to illuminate each sensor photocell as desired and capture arbitrary light the physical way. But as another commenter pointed out "it's forgery-proof" ;)