I booked my trip and used a 40% discount pin. Everything is paid for. After reading some of these stories I am terrified that I am going to get there and be told I have to pay even more money! Am I overreacting? Can I call to make sure this does not happen???
Answering a couple of questions will confirm whether or not a freak-out is warranted.
First: Have you saved ALL of your confirmation details that you got from Disney? If you booked through them, print out all e-mail correspondence. This doens't guarantee that a problem won't happen, but it helps. However, this is is really not a major factor regarding the price "changing". So, even if you haven't saved or printed anything, I wouldn't freak out over that.
Second: Was it really YOUR Pin Code? If it was, I wouldn't think you should worry. It would also be helpful if you saved the postcard and/or e-mail with the code number, but like question one, that isn't necessarily the crucial point. I would be a "little" freaked out if I hadn't saved the PIN codes, but only a little.
IF, on the other hand, you managed to use someone else's PIN Code, or scammed the system in any way - then there may be a good reason to freak out. Apparently, a lot of people got away with this last year, but some got caught too.
Really, trying to cheat is the most likely reason for a "price change" If you didn't, I wouldn't worry at all.