Option - sure, but each time it should come with customer’s consent, as per Mastercard rules. Seems like they’ve been slapping you with DCC without seeking your permission first, which is a breach of Mastercard rules.
I did wonder if this was the case and didn’t think I’d be the first. I was aware of DCC at ATMs but I’d never seen it on a PDQ device before. Turns out searching for “POS” and not “PDQ” could’ve avoided a n00b first post
Pretty busted for cash withdrawals in Morelia, Michoacán for what it’s worth. I think I managed one withdrawal at Mexico City airport but none of the ATMs in Morelia worked, even those clearly marked with MasterCard logos. On the other hand, payments for goods, meals etc. all worked flawlessly.