i highly doubt that. look at the the f 22 raptor. it uses its shape and radar absorbant materials to deflect the radar signal. you mean to tell me that, that brush on application can absorb radar signals? the f 22 uses a computer to tell when its radar signature has been reduced. so does our government have less technology for radar diffusion than this company? why doesnt the military just buy a shitload of this and coat all their planes with it? wouldnt it be a lot cheaper than spending millions of dollars on the design of a stealth aircraft? and just brushing that stuff on the headlights and a few other parts is going to protect the whole car? i dont buy it at all
You will get no debate from me that passive "radar" defense is nothing more than snake oil outside of the military defense industry. And active radar defense requires a substantial emitter and is illegal by federal law.
Radar detectors are neither passive or active. They are simply receptive devices. The perceived "passive" part of a radar detector is your vehicles brakes.
However, passive defense of LIDAR is not quite so cut and dry. In theory, its a fairly simple concept. Maybe the best way to demonstrate this is by example; all you need is removable diffuser from a camera flash and a visible light laser. Shine laser on a light colored wall and them move the diffuser over the beam and see what happens. The prisim effect you see in this example is an effective counter measure to any light emitting/laser device such as LIDAR.
However, here is where the leap from the theoretical to practical application gets difficult real quick. In theory, a lens over a license plate "may" be an effective diffuser for the license plate. But there are so many other factors that come into play such as the reflectivity and luminosity of the plate, the distance the lens is offset from the plate along with the power, angle and wavelength of the LIDAR beam. You would have to effectively design each license plate cover/lens to a specific application. Its just not feasible.
Now think about addressing those same obstacles in a thin film or spray on film application... more snake oil.
And as others have noted, any license plate cover or lens that blurs or diffuses your license plate will get you pulled over in a heart beat.