The opinion begins:
Alice in Wonderland has nothing on section 518 of the New York General Business Law. Under the most plausible interpretation of that section, if a vendor is willing to sell a product for $100 cash but charges $102 when the purchaser pays with a credit card, the vendor risks prosecution if it tells the purchaser that the vendor is adding a 2% surcharge because the credit card companies charge the vendor a 2% “swipe fee.” But if, instead, the vendor tells the purchaser that its regular price for the product is $102, but that it is willing to give the purchaser a $2 discount if the purchaser pays cash, compliance with section 518 is achieved. As discussed below, this virtually incomprehensible distinction between what a vendor can and cannot tell its customers offends the First Amendment and renders section 518 unconstitutional.
Prior posts on the case are here.