That's what I intend to use hazard function for. The "flash-to-pass" button is on US bikes - that's the little trigger on top of the left hand control that activates the high-beam headlight. A hazard function would make the turn indicators flash in unison. If I understand the circuit diagram that I linked below (which admittedly is for a muuuuuch simpler circuit from an old Volkswagen than what actually exists on our bikes), a switch wired to the correct pin of the flash relay would create the desired effect.
My hope is that they fab the bikes with that pin wired into the cable regardless of where the bike is headed and I would just need to connect a switch at the handlebar. If an EU/UK control could be swapped in, and that hazard button was on there, that would be an easy enough solution. Too many ifs ...