According to the Nebraska Secretary of State's website,
This statement begs many questions, like "What constitutes an insult," "Does the law apply only to Nebraska residents" and "What are the penalties?"
So let me first approach it from this angle: Are you aware of a resource that offers a good overview of laws pertaining to the treatment of U.S. state emblems and/or the history of their enforcement? Ultimately, I'd like to compile a list of states that have similar statutes along with records of people who have been prosecuted for insulting emblems.