Originally Posted by
kilton
Basic question: How does one quickly detect that DCC was used before signing the receipt?
Check the amount: unless the two currencies are trading on a 1:1 basis, the amount will be a different number from what you would be expecting if it was being charged in the local currency.
Of course, you might not always have an exact idea of the amount (e.g. when checking out of a hotel) and some currencies are near enough that confusion could occur (e.g. the US dollar and the euro): there will also be a note of the currency somewhere on the receipt to be signed (and if there's not you should be kicking up a big fuss anyway).