Past experience is that CX often allows short checking luggage, ie , often luggage allowed to be collected in HKG and sometimes the passenger does not fly onwards.
However, with this mistake fare, CX is honouring the very cheap fare (to the surprise of many here) on the basis that they will stick to the letter of the contract although the price is surprisingly low. Now, should the parties not also stick to a clause in the contract that in the absence of the passenger flying the entire itinerary the fare will be recalculated? Surely, yes. Is this counter-intuitive? No. If CX were to hold passengers to the contract in the same way they hold themselves to the contract, will they get bad press? They should not. People will say to those lucky ones who got a good deal "good for you" but if they decide to push things too far, people will say that it is CX's duty to protect company revenue and shareholders' interest. Let the Courts decide. CX will not be the first airline that enforces the clause of flying the whole itinerary.Those who booked the lucky fare left their credit card and other details with CX. Short checking bags or not checking in any bag actually raises a flag and CX will have good evidence to show the Court that skipping the last leg was pre-planned.