My mother just went to Austria and got completely hosed on the DCC at the airport of all places(Euronet ATM I'm guessing) at 15% markup and she did it twice! she couldn't read the screen so clicked yes, Schwab had it written explicitly in their conditions that this would not be refunded so that was super painful ($1k Euros). I had only seen videos of these ATMS and not in person after visiting 20 countries (although not eastern europe)

Separately, was in Ireland and the Quinlan fish bar in Killarney and waitstaff insisted the machine would only charge in the currency the card was issued in which I know is not true but I didn't have time to argue with them or make them redo the transaction. I'm pretty sure even if that's the default there is a way to bypass. It's only $5 dollars (3.5%) but it's the principle of the matter and the waitstaff was all snooty about it. Chase doesn't actually have this as an option for a chargeback but VISA does if I recall correctly?
https://durangomerchantservices.com/...ations%20where