It is nothing new.
But I don't see them very often, and I had one example on my dash-cam.
This is how it looks like in action, in real life.
https://youtu.be/AVRXL2Mb2EM
In this particular case, it worked (sort of), as the rider was wearing mostly all black.
Ha Ha those hotdogs! I see a lady rider on the 110 here in los angeles use one of those helmet lights. It looks to be one of these
https://www.brakefreetech.com/ (https://www.brakefreetech.com/):