By the way, consider that what your eyes can see isn't necessarily the same as what other's eyes can see. Age, vision, sun's position on the horizon, reflections off vehicles and buildings, drivers in vehicles with dark tinted windows, etc. etc.

One time while out riding, I didn't see a fast moving roadie wearing dark clothing while they were approaching under the shade of a tree line, even though they had a white blinky up front. The problem was the blinky just looked like a reflection off of anything else that was down the road. So, the invisibility of the rider/bike made it look like that "reflection" didn't belong to anything moving my way.