Well the rules state that the customer must be given a choice for DCC, for small transactions that dont need authorization naturally the default should be local currency since you can't choose anything.

Thanks for the heads up all on deceptive choices on the terminal. I will be sure to decline anything that looks like an exchange rate or US dollars anywhere. I know some airlines are also deceptive for online transactions. Like you will be given a choice to choose between a set exchange rate (DCC) or an unknown rate. Naturally most people don't want to risk the unknown even though the interbank rate even at its worst is still less than DCC.