I believe if they charge you a rate more then what it says on the back of the door, then they did so knowingly.
Those numbers didn't get there on their own.
I have never seen a hotel where that rack rate was anywhere near what I was paying, always wondered who would pay $600 for a room I'm paying $150 for. Wonder if somebody took a card and that was an old one behind it or something from 20 years ago.