With the landing costs at some hotels, I would have thought that an armed guard was included
I have a rape alarm with the trigger that is operated by a thin string looped around door handles very loud and has deterred a curious geek I heard it 100Yds away at a sort of fly in.
There are all sorts of Phone operated alarms made for vehicles, costly but do have voltage free switching outputs.
If you are interested PM me
Remember Cellphone cover is not universal.