Just in case anyone is visiting Australia you should know that Credit Card surcharges are common (and legal).The merchant must clearly advise you of the surcharge up-front and the amount must be used to cover the costs incurred by the merchant and not as a "profit centre". It's typically somewhere between 0.5% and 1.5% for Mastercard and Visa. Amex is often higher at up to about 3%.

Hilton in Australia charge 1.5%.