I'm not sure where the blackmail would come from. What I'm talking about is a situation to detect employees just hitting HKG on all DCC transactions without asking the customer, as has been reported to happen in some cases upthread. I would guess that an employer implementing DCC would want each customer to make the choice themselves, and an employee that just chooses HKD for every transaction without asking is depriving the employer of extra money and from the employer's perspective is not doing their job properly. From my point of view, the whole of DCC is based on taking advantage of uninformed customers and shouldn't be allowed at all.