I can tell you that any kind of cover even if it's clear in the State of New York is Illegal. You cannot put any covers over your taillights, headlights or license plates. Ofcourse since it would be sprayed on, it would look like just another aftermarket taillight or even stock for some.
I would go the spray over any kind of plastic smoked cover. They can't prove you have spray unless they scratch it off, which is something they cannot do unless they have proved it first. (basically, they won't touch do much of anything, but the covers you'll get a ticket or they will make you pull them off.)

 

I can tell you that any kind of cover even if it's clear in the State of New York is Illegal. You cannot put any covers over your taillights, headlights or license plates. Ofcourse since it would be sprayed on, it would look like just another aftermarket taillight or even stock for some.
I would go the spray over any kind of plastic smoked cover. They can't prove you have spray unless they scratch it off, which is something they cannot do unless they have proved it first. (basically, they won't touch do much of anything, but the covers you'll get a ticket or they will make you pull them off.)

So, to make a long story short, it depends on the state and ticketing officer.