I take it that currently the US would have no jurisdiction to seize assets from a Japanese company, in Japan, but if those assets are now held in the US, by a US company does that not open up that kind of situation?
To my understanding USD is always held in the US, banks in Japan or any other country have holdings accounts with US banks, so if you have a currency account in another country, the USD still are in the US, it only appears to you they're not.
https://bitcoinfoundation.org/blog/?p=63