Agreed if you are a 100% bona-fide US registered, domiciled and operating company, you will be obliged to allow employees to fulfil their USERRA and defense obligations.
I feel the question will be whether the legal minds decide which side of the HKG/USA fulcrum are the base guys sitting.
By way of example, take NZ 'based' crew and compare with Aus 'based' crew. Separated only by a small patch of water, 20 years in time travel, and the abilities of the AllBlacks rugby team, they are ostensibly very similar, but subtly quite different.
I believe the NZ crew may be effectively a HK company, and despite a NZ court ruling of recent which CX is seeking leave to appeal, means aspects like income tax could indicate contracts are favourably swayed to the HK side.
Conversely, the Australian mob are fully onshored, Australian company, and a soon to be (if it passes the vote) ratified EBA (Australian contract). that is likely to cover reserve/defence force aspects.
Sure any case held in a US jurisdiction will have a US flavour and degree of not quite so impartial bias against a "who the f*ck does this HK company think it is?" attitude of the dip**** complainant, but hopefully the individuals adjudicating on the case will decide which side of the see-saw fulcrum the US based/ HK contracted guys sit.
I see Mr "cut the line" received a 3 year probation for his well thought out plan of impersonating crew. He sounds like a fine upstanding character with integrity and morals that could be depended on. Quite un-befitting for a USN Officer and aviator.
If he achieves nothing else than being a thorn in CX's side, he may at least have cleared the muddied waters of US basings, and perhaps force the company to declare their hand and fully on-shore like many of the other based areas.
That's the price one has to pay for doing business in 1st world countries.