All vehicles are required to have rear reflectors for safety reasons. Guess you could tint them but I'm not sure why you would want to.
That is a technicality which requires explanation.
For instance...not every vehicle has a pair of separate reflectors like the NOX
They can be built into the taillamp housings for instance
But if the shape and design of said housing does not facilitate reflectors built to code...well then...
You get the Fugly NOX style...which could be equipped with bulbs to illuminate if an enterprising Modder was motivated enough