Personally I would vape in my state room--have vaped in nonsmoking hotel rooms--like you said, there is no lingering smell.
I am not big on confrontation and vape discreetly in non smoking areas.
hold a finger over the light and hold the vapor a few extra seconds--this results in very minimal exhalation of vapor. I have smoked in many non smoking areas without any difficulty.
So far so good for me, but then again I prefer to stay under the radar. I have vaped on airplanes, in airports, non smoking casinos, work, walmart, target etc.
enjoy the cruise !!!!!!