Do plate/tag covers work???
Here in Massachusetts, a lot of police cars have automatic laser tag readers, so that every car that the cruiser passes gets a look see by the big computer. They make a lot of low priority arrests as a result of catching folks with outstanding warrants.
Now a lot of folks are putting laser defeating covers over their tags, so that big brother can't track them. I note that the majority of the speeders on the Mass Pike have them. Do they defeat radar too? I don't see how they could.