i mean the pax presumably did not want to buckle up and take their seat? that in itself is a safety violation. And is not obeying the lawful instructions of air-crew also an offence and grounds for arrest? And if they don't want to go, resisting arrest is another crime? think its different from the david dao incident presumably because they have the court of public opinion on the ISM's side (but obviously with social media these days, it could well be this turns out different).
Best way is for CX to request HKG police to press charges and haul them up to court. Let the law deal with it.. even better if they get a criminal record or get onto a no-fly list.