Jurisdiction
I have not read the book, so I don't know if Fannie Flagg is responsible for the writing the of two legal circumstances in the film.
First, when Evelyn does the Towanda on the VW - that's a criminal act as well as can be pursued in civil court. So, nothing about it was elaborated upon except Ed bitching about it. Maybe Evelyn got some community service which was not relevant to the film.
However, having Idgie stand trial in Georgia for a possible murder in Alabama just don't happen. The trial would have been in Alabama.