In Maine illegal attachment of plates is in violation of 29-A M.R.S.A. 2104. Here it states that a person commits a Class E crime if that person attaches to a vehicle a registration plate assigned to another vehicle or not currently assigned to that vehicle. This is a strict liability crime.
A Class E crime in ME can allow you to be arrested and go before a district court judge. The maximum term for being found guilty of a Class E offense is 6 months and a maximum fine of $1000.
If you have been cited for illegal attachment of vehicle license plates then call the court listed on the ticket to find out more about the penalties you may be facing.