I know it depends on which state you're in but I can't seem to find a straight answer. Right now I reside in Texas but I'm moving back to Massachusetts in a few months. Here's what the law in Texas says...


A person commits an offense if the person attaches to or displays on a motor vehicle a number plate or registration insignia that: (1-4 omitted here)
(5) has letters, numbers, or other identification marks that because of blurring or reflective matter are not plainly visible at all times during daylight;
(6) has an attached illuminated device or [is a] sticker, decal, emblem, or other insignia that is not authorized by law and that interferes with the readability of the letters or numbers on the plate or the name of the state in which the vehicle is registered; or
(7) has a coating, covering, or protective material that:
(A) distorts angular visibility or detectability; or
(B) alters or obscures the letters or numbers on the plate, the color of the plate, or another original design feature of the plate

 

All laws are open to interpretation so its a matter if the fuzz want to use it against you, and who the judge is going to side with that day. That said, I have never had any hassle from the fuzzsince I began running them about 15 yrs ago. I have them on all my vehicles that have tinted windows. Included a 5.0 mustang with limo tint and a non-street letal exhaust that attracts a lot of attention. It all in being in the wrong place, at the wrong time, and doing the wrong thing. Screw it man, just put on the tinted covers and enjoy. You only live once!

 

I had a plate cover that was "smoked" a while back, and cops used to tell me it was illegal, but i never got a ticket.