Ooops! No doubt there's a lot of people having to find the answer to your first question (the "how").
Presumably the second part is related to whatever advance passenger information that the airlines have to give to the destination authorities; turning up with an unannounced passenger might attract a fine of some sort. I don't know if Japan requires such information, but that'd be my guess.
I do wonder though if the "return" counts as having left the USA or not; they're returning with a whole plane load of people whom the authorities weren't expecting.