How do you deal with hotels where there is a pre-authorization? One of the few times I got hit with DCC was at the Venetian Macau, but I had no idea it had happened until it was too late.

So with Harrod's and associated merchants it'll be an uphill battle to get them to avoid DCC? Do they not know how or are they simply unwilling to disable DCC?

Finally, from what you've indicated, you're screwed once you see the DCC quote slip in Mainland China. I don't know if HK or Macau are any better. As I've stated here before, I've always had the selection on the quote slip honored in Taiwan and have been successful in preempting the quote slip by asking to be charged in Taiwan dollars before the cashier runs the card.