These are not necessarily Errors, but made for special circumstances
as-needed I don't know who the "National Coach of the Year" was in 1979 (or earlier), nor for which sport; issued as needed.
as-needed Miss South Carolina plates issued with the year of reign; unknown if plates are kept past reign
as-needed Provided for special events such as National Governor's Conference or for former politicians.
1991 The Wren base won ALPCA 'Plate of the Year'
attendees were able to tour the plate facility and received these as souvenirs
1991 The "Fortune 500 Forum" was held in Charleston in November, 1991. I believe that these plates were 'street-legal' for attendees
Flat, with screenprinted "EXPIRES 11/19" in lower left corner; "91" in lower right corner.
1997 from http://www.whitworthfamily.org/aamva.htm The AAMVA (American Association Of Motor Vehicle Administrators) is a tax-exempt, nonprofit organization developing model programs in motor vehicle administration, law enforcement and highway safety, in the United States and Canada. The AAMVA has a convention every year somewhere in the United States or Canada. For many years the State/Province hosting the convention would manufacture "special" license plates for AAMVA attendees.
These plates were never 'street-legal'.
2000 no information - NAIA could stand for National Association of Intercollegiate Athletics -or- National Animal Interest Alliance -or- National Association of Independent Artists.
I have found no information on any conference or team that this plate could have been made for.
plates "smuggled" out of the prison, presumably contraband souvenirs