Last spring I received a postcard offering something like this:
"Now that you've experienced Disney Moderate resorts, how would you like to try a Deluxe for the price of a moderate?" (maybe not word for word, but you get the picture)
I guess I got lucky. In reality Disney probably identified me as a Moderate Resort frequenter, and hoped I would become a Deluxe resort frequenter. It's pretty smart business really, and it kinda worked. I stayed at the AKL & WL last year.
The fine print on the card was that it I was able to get Standard rooms at WL or AKL for the price of a moderate (about $115). Even with Standard rooms, that was still an unbelievable deal, especially since I was upgraded to Savannah view at AKL. If I wanted BWI, YC, or BC it would still have been discounted, but it would have cost more.