During my travels, I came across a POS device that would access DCC options after tapping or chip. Then it would show a message that was too quick for me to take a picture which clearly said that only the customer can select the currency choice (for devices that are not consumer facing). Then, the two flags would show up with the local currency/country and the converted option.

I think it is a good reminder that when you protest a DCC it is about not having a choice. Although, it seems that in many cases our local issuers eat the charge difference.