A financial institution may not use a firearms code to engage in the following discriminatory conduct:
(1) Declining a lawful payment card transaction based on the assignment of a firearms code to the merchant or transaction;
(2) Limiting or declining to do business with a customer, potential customer, or merchant based on the assignment of a firearms code to previous lawful transactions involving the customer, potential customer, or merchant;
(3) Charging a higher transaction or interchange fee to any merchant or for a lawful transaction, as compared to the fee charged to a similarly situated merchant or for a similar transaction, based on the assignment of a firearms code; or
(4) Otherwise taking any action against a customer or merchant that is intended to suppress lawful commerce involving firearms, firearm accessories or components, or ammunition.