A seller shall immediately notify the city of any fire, theft or other casualty which prevents their compliance with this chapter. The casualty constitutes a defense to any penalty provided in this chapter if determined to be the proximate cause of the failure to comply for a given reporting period, but does not excuse the seller from liability for taxes due. Accidental loss of funds or records is not a defense against penalties of this chapter. [Ord. 17-39 § 2.]