There have been mysterious, anecdotal reports of staffed terminals outside the USA requesting a PIN from American cards, which the clerk "over-rides" to force the sale through. As far as HD goes, I could see their programmers having omitted PIN altogether as an option fearing it'd slow things down, so everyone is automatically funneled into online signature (credit network ONLY for debit cards) as the sole EMV option; a card that didn't have that anywhere in the CVM list would fail.