Grand Theft Auto is a 1977 American comedy road movie directed by Ron Howard. It was Howard's feature film directorial debut, and it features Howard as Sam Freeman and Nancy Morgan as Paula Powers in the leading roles. The film takes its title from the crime grand theft auto, which is committed a number of times by several different characters.
Grand Theft Auto was inspired by the show Happy Days.
Ron Howard starred in the show Happy Days. You cannot tell one way or another if his experiences there contributed to the movie. I believe the system marked it as incorrect because it is improbable, but not impossible.