Concept Bikes & Bike Innovation - for better or worse

From the video, they are multicoloured anyway since he has them set up as a colour-based speedo.

Not 100% I understand what you mean, but the RGB spectrum can easily be manipulated via the controller, reprogramming it wouldn't be particularly difficult. Might even throw a switch in there.
Not disputing the pointlessness of having a rear facing light, but just saying the tech is available to chance colour at will.