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.
The are already seen as HKG companies.
"On October 3, 2001, plaintiffs filed this action against CPA, USAB and Veta, as well as the two individual defendants. The three corporate defendants are incorporated in Hong Kong and have their principal places of business there"
"The record demonstrates that a Hong Kong employer terminated the nine plaintiffs for conduct that took place in Hong Kong. California has no interest whatever in deterring or regulating the adverse employment actions taken by a foreign employer with respect to non-resident foreign national employees for conduct and activities that took place in the foreign jurisdiction. Moreover, it seems clear that plaintiffs' employment, as well as its termination,
are governed by the law and relevant civil aviation regulations of Hong Kong and the terms of the union agreement between HKAOA and Cathay."
Basically that case said they should have first been heard in HKG before clogging up courts in the US with foreign issues.
Keulen v. Cathay Pacific Airways - California Personal Injury Lawyers