What will they do if it doesn't fill? They're looking for another few hundred people who a) feel trained enough to run a marathon in a month, b) can afford a trip to Disney with only a month to plan (can you say "rack rate")
I'm really starting to wonder if it will actually fill this year. (now they may close registration at some point so that they can get on with the paperwork, but I wonder if it will actually be full)