But in this case I presume you tick the currency selection box, sign, and then the waiter goes back to input the final amount into the terminal? I assume it's similar to your example of A Lorcha. If so, I think you'd have strong grounds for a dispute if your currency choice wasn't honored since the merchant presumably would have the original and you'd have the carbon copy showing a currency choice ticked and signature.

I noticed in the example of the receipt at A Lorcha that there is a box for a tip, so I'm wondering if that could help avoid DCC? It's not as relevant between MOP and HKD, but take my USD denominated cards and compare to MOP for that receipt. For example let's say the markup was 2.7% like on yours to 72.59 USD (real exchange rate of 70.68). I know that part of the world doesn't have a tipping culture, but let's say I left a modest tip on the 564.30 MOP bill of 60 MOP, write a total of 624.30 MOP, and tick the MOP box. I would be livid if I saw a charge of 132.59 USD, and I don't think the waiter would perform a conversion of 60 MOP to 7.51 USD on the fly. It's also possible they wouldn't enter a tip at all, but I don't think the waiter would forgo one. Thoughts on this approach?