Nope. Mop is the legal tender, pegged at mop103 to hkd100. All merchants are supposed to bill by that, even tho hkd is (and merchants prefer) hkd cash payment at 1:1 for obvious reasons.

Because mop is the legal tender, card terminals bill that as local currency without exception (not sure if true for gambling advances inside casino, never tried that)

Regulators are not as strong there (and dare I blame them for being closer to the motherland than us?) DCC is rife.