License plate covers aren't supposed to pass a yearly WV State (safety) Inspection. Along with head light covers, tail light covers, tinted windows darker than (?) percent, any lights not factory installed (except for emergency vehicles).
in ontario, all the above illegals exist. there was, however, a ruling issued by a provincial court judge, several years ago, concerning tinted glass. the law states that u cannot have tinted glass that is so dark that a police officer is unable to clearly view the driver and any passengers in the front seat - officer safety. the judge, in summary ruled that the law was not enforcable because all people require levels of light to view the same object. the police have to use a device to measure the amount of light that can pass thru the tinted glass. and they do not have this instrument.
Looks like good info, state by state: http://www.ncsl.org/programs/transportation/tranrev2.htm#top Devon
