Good points Wes.
I'm just thinking out loud (that's me thinking below)...
one of the issues with that is you would have to have hookups for the generators. You have to have a port for such things. So if everything is hard-wired in; it might borderline impossible trying to tap the lines with an alternate power source.
Even if there was that ability, they would have to run some pretty heavy size cables from the deck, down several floors into the engine room and stuff.