I would be especially surprised because such credit card surcharges are illegal in many states (incl. California), and contrary to credit card issuers' contracts. If it were me, I would seriously consider paying the surcharge, then disputing it with your bank. In California, by law you're actually entitled to recover three times the surcharge wrongly collected -- so in principle you could even make money on the surcharge (putting aside the time and effort required to collect, which could be considerable).