The Indiana Court of Appeals has determined that a challenge to an alleged ordinance violation can go forward even when the alleged violator pays the fine imposed by the municipality. In Dempsey v. Department of Metropolitan Development, a landowner was cited for violating the Unsafe Building Code. The landowner paid the fine in order to prevent the property from being sold at a tax sale. The Court determined that this preventative action could not moot the challenge to the imposition of the fee in the first place.
The opinion can be found online at: http://www.ai.org/judiciary/opinions/pdf/08161101jgb.pdf