Just got back from a week in Ireland. Encountered DCC at the vast majority of merchants (hotels, restaurants, gas stations, small shops) but every time was either asked by the cashier if I wanted to pay in Euro or Dollars or I had the chance to press the corresponding button on the keypad. I noticed several of the readers had a second screen after I pressed Euro that asked the merchant to confirm the customer refused the DCC "offer". I didn't have any issues with merchant pushback, I did observe several other Americans selecting to pay in Dollars including at a very expensive hotel, so there's obviously a lot of money in this for the merchants and banks.