That may not be worth much. It's hard to tell without knowing more details. Some mistake rates show up on websites, but then are transmitted to the hotel correctly. Most people would find it quite unpleasant to have to argue their case at check-in. Generally, if your booking isn't pre-paid, then the odds of getting your rate honored are lower. For future reference, just post your finds here while they are active, and then FTers can be counted on to put up a good fight.