What about the UK 'reflectance' requirement (if thats the right word)?
They break it, the law states they must be
made from a reflective material. Metal is not a reflective material it is painted to be so. There was a large crackdown around here a couple of years ago around Weston Park at a VW cruise where they stopped cars with presses plates. They need identifier marks in them as well.
The companies that sell these saying they are legal are not being truthful.