I wouldn't be worried at all about vaping in a hotel/motel room. If it's a non-smoking room, then you are still ok, because it doesn't say "non-vaping".

Think of it this way, if you vape in your room, and it sets off the smoke alarm, then you can compliment the hotel and sleep comfortably, knowing that you are SERIOUSLY safe in that room!
I have vaped in hotel rooms all over the place, and never set off a smoke alarm.
Lastly, when someone comes to investigate, should you actually set a smoke alarm off, the room won't smell like smoke, so you're all good.