I am very very surprise that it's 16 years since 1997 hand-over. CX is 30% owned by Air China. CX/KA flies tons of flights daily in-and-out of China, and CX and China don't have any type of agreements in place to handle situations like this? While these things don't happen everyday but if anything goes wrong at HKIA then the multiple Chinese airports in the area are logical options for emergencies and contingency plans should have already been proposed and approved by both sides by now. Even if it is simply to disembark the plane and get them to rest in the lobby is better than getting stuck in the plane for 17 straight hours.