Originally Posted by percysmith

There's still one way, much easier to do here than China - try DCC and ask for HKD billing first. Deface any slip that has verbage (don't rip up the slip, but write /VOID/ across it - we still have Bills of Exchanges law). Ask for a void - I can't think of any merchant here who can't void a slip if asked - and present alternate payment, be it Amex, Discover (as Unionpay - I'm not sure if they work here but it might be possible - someone please report back) or in the worst case cash (USD/HKD spread is not high - you'd easily get 7.76 for your greenbacks).