Yup. Exactly, Zapp. And the other thing is that the company has contracts in jurisdictions where it cannot be easily modified (certainly not without the consent of the contractees). Seniority is the most clear cut thing in the contract and it's literally in black and white. So in some of those areas it requires layoff in reverse seniority order with definitive pay protection for those laid off in any case according to their contract. And those contracts are enforceable through the grievance process and/or court.
And it's not like the company could shut the base with the intent to dodge this responsibility on an existing contract. If this scenario occurred it almost certainly would go to court and relevant inter-company comms subpoenaed. Kind of like defrauding the residents of a town and then skipping town (with some type of store still in that town and a business in other towns). The officials would go after your store in that town and you certainly couldn't do business there anymore--and may well be able to attach assets from other towns to the debt.
In fact, given that the company has been paying taxes in the US for a degree of work performed there even for HKG based pilots, this might be one avenue for even those aggrieved there to pursue relief.
Like I said the contract is clear. If they want to furlough out of seniority they will have to pay those with seniority to allow this to happen (and the only real way to do it on some of the collective agreements would be to pay those individuals what they believed to be a reasonable sum to voluntarily leave or take a temporary hiatus). Or they will go to arbitration/court and lose anyway.