You pay monthly for HBO (or cable, etc). You pay monthly for Netflix (many of whose shows were on cable TV first...).
You put an HBO movie on you owned DVR. You put a Netflix movie on your laptop's hard drive.
You take your owned DVR on a cruise. You take your laptop on a cruise.
Really, if they're not distributing it... isn't this just time-shifting? They've already paid for a license to view it, after all, and last I knew, time-shifting and even location-shifting was legal if there's no distribution taking place.
For that matter, if I add a TV tuner card to my PC, and use that to record an HBO series, part of which is already on Netflix, to my hard drive, then take that on a cruise....
Then there's that device that lets you view your own local cable broadcasts when you travel, even across the country...
Fuck it, do what you want. It's not as though anyone will be losing any money, after all. The OP already paid for Netflix, and it's not like they're "stealing" temporary premium content to publicly display...
In fact, the only one with any real standing to complain is the owner of the cruise ship, who will lose out on huge data fees due to the workaround.
I'm not all that certain this can even be called "piracy", since by having a Netflix membership they've already paid for a license to view any of the streaming content anyway (and potentially on multiple devices at once, no less). You can't even say "but they're not saving a copy when they're streaming" since that actually does happen to begin with. It has to cache somewhere, right?
I'm calling this a grey area favoring the user. As long as there's no distribution, I don't eeally see a problem.
IANAL.