In theory I agree it is helpful. However, I wonder how many individuals will get ticketed just for having something obscure some part of the plate. Furthermore, if they are looking for a particular vehicle, say a 2010 White Camry, what would be more specific, one from “Sample County” or one with an obstruction over part of the plate. I submit it would be the latter.
I recall a story where the police asked for surplus night vision equipment under the homeland security financing. What did they use them for? To ensure individuals were wearing seatbelts. Yeah, it made sense they might need the vision enhancements to spot terrorists at night (assuming they knew what they looked like) but of course that became secondary to raising money.
And you would be wrong.
Narrowing down the 2010 White Camries in Sample County is much easier than searching for all of them in the state, which may or may not have an obscured plate.