He is talking about Photo Blocker a spray that goes on your licence plates and when you run a red light or the police are doing photo radar your plates reflect the flash like taking a picture in a mirror with the flash on.
I think a company called Phantom Plates sells it and I saw it on the news that the police are not happy about it because it "helps" people break the law. No it doesn't look as nice as the tinted licence plate covers but from the news segment I saw it appears to work. I was also wondering if anyone has tryed it?