Some outstanding rules of the association include rules about how a cardholder must be identified for security
, how transactions may be denied by the bank and how banks may cooperate for fraud
prevention, and how to keep that identification and fraud protection standard and non-discriminatory. One notable rule is that no merchant accepting Visa, whether a mom-and-pop store
or a government
body like a university
, may establish any minimum purchase, maximum purchase, or surcharge
for any Visa (credit) transaction (except for in Australia and the UK, where recent legislation in each has allowed retailers to apply a surcharge on any credit card transaction, VISA or otherwise). They can establish surcharges for debit transactions (although lower fees on debit card transactions means that merchants typically encourage use of debit cards by surcharging more for credit cards, where allowed). Enforcement of the rules, however, is by individual banks, and they may or may not know the rules well. So, a restaurant
may charge a surcharge or minimum, which may at first be upheld by the bank in many cases, unless the consumer knows the association rules well. Other rules govern what creates an enforceable proof of authorization by the cardholder (starting from a signature or PIN), and continuing to lower levels of proof such as a shipment accepted or a statement by the consumer.