I recently returned from Spain and found contactless DCC very widespread. All compliant and nothing forced, but the currency choice appears during the authorisation stage, so you may need to keep hold of the reader (if portable) until the transaction has completed. The terminals with touchscreen also had a second "are you sure you don't want to be ripped off" screen, where you have to touch the red box on the screen (but not the red cancel button) to opt out of DCC.
Does anyone know how DCC works (or does not work) with Apple Pay and Android Pay. Who does the currency conversion? And is DCC offered?