Clearly, demand to China (and HK) is extremely light. Looking over the next couple days, flights to HKG are wide open in all classes, though at least several are far from empty. Notably, premium cabins appear emptier than Y. So the business case for reducing service is probably more than sufficient.

However, I wouldn't be surprised if management was getting flooded with calls from nervous crew. I don't know what the rules are, but can crew outright refuse to serve a destination for safety concerns? Is that covered by their CBA?