Matt_L, thanks for posting this. It prompted me to check my recent Hong Kong transactions and discover that I was DCC'd by the Courtyard by Marriott Sha Tin's restaurant on my Citi Prestige card.

It doesn't match your exact scenario -- the charge on my account showed only USD, whereas all the other charges show the billed HKG amounts for reference, so this seems like just a case of not respecting my choice. When I called in to dispute, the agent said the conversion had been done by Mastercard, but I'm not sure she could really tell.

This was my first time disputing with Citi. None of the on-line options was helpful for DCC -- the "Incorrect amount" option asked me what the amount should have been, but it wouldn't accept letters (e.g., HKD). The "Other" option resulted in a prompt to call. They immediately refunded the difference (after taking me at my word for what the amount should have been, based on the exchange rate!). I also pressed for follow-up with the merchant; they said they would -- hopefully it's true. I may write the hotel, as I stayed six nights and the staff were great, but not respecting a DCC choice is a serious black mark.

Seth