Your words as posted up above:
If this were two rational people elsewhere in the world, everything you say later on is quite logical, but if you bring someone back to your room who is "a bit drunk", you're playing with fire. Maybe she was too drunk to do what you hoped for, and throwing her out of your room, giving her no money, seems like you're just asking for trouble.
Hindsight is always 20:20, but really, if someone is quite drunk, and you bring them back to your room anyway, they may simply pass out on you as soon as they lie down. You're already setting up what could be a bad situation. And if you throw them out of the room you've just brought them back to, after partying all night, and don't give them anything, that just seems like an accident being set up to happen.
The whole "scam" thing is obviously wrong, but when you do something nasty to a person who's already drunk, YOU are the one setting up the scene.
I can relate to what you're saying, but maybe the smarter thing would have been to just go to sleep, and hope for better things in the morning or whenever you both woke up.