I usually book the hotel around this time as well, but I was saying that every year word starts spreading that the hotel is booked up, and every year lo and behold, more rooms show up. I'm not saying it's not true that the hotel is full, but I'm just saying, don't get too worried yet. The Kumoricon staff have been doing this too long for something that monumentally troublesome to happen (the hotel getting booked before the code even gets released).
Then again, if that is the case, then yeah, I'll be the first to say it's messed up and should be addressed. But, that's a pretty unlikely if.