Sounds like a the problem was you inviting a total stranger to a room in the first place. If they saw you walk in with someone and proceeded to take them up to your room i would have thought either your wife or girlfriend. These people are skilled at doing these kinds of stuff and lying their way through these situations. If you fell for her lies then the FD agent may have too. No good deed goes unpunished. Im not saying the hotel is not at fault as well but you are putting all the blame on them when its not.