Welcome to the world of international travel. Oh, and whoever said "life is fair", was lying.

You need to keep abreast of exchange rates so when you do check out you can very quickly check if they are in line with expectations, and if they are not, then plan to speak with the manager. The planning part means, make sure you are not in a rush to get out the door and to the airport. I always allow myself extra time whenever checking out of any hotel, whether it is to get BB, exchange rates, just check over the bill and room charges, etc. It always pays to be just a little bit OCD.