Originally Posted by
Zorak
9% at BCN airport ATM

If you do the calculation it's more like a 16.7% markup versus the true exchange rate.
Originally Posted by
rjn21
The final bill was presented in €. Mastercard inserted into card reader and € amount shown. PIN was requested and entered. No choice of currency was offered.
I then gave back the card reader. Then, after PIN entry for the € amount, DCC was offered in GBP (my card currency).
I don't know about Mastercard's rules in this instance, but as a best practice when entering a PIN I would retain the card reader until the receipt started to print.
As much as I like PIN preferring cards, this is one instance where chip-and-signature wins since it's always possible to refuse to sign and have the merchant void the transaction or deface the receipt and take a photo for a chargeback.