This is value season. We were there this year for a week throughout the MLK weekend. We didn't find it too crowded, but on several nights they were turning folks away at the restraurants we were at unless you had a PS (The Plaza and 50s Prime Time).
I do still have the AP email for the release of AP rates during this timeframe. It says: "Rates available most nights 1/2/05-2/16/05. Not available at all from 1/14/05-1/16/05, 2/3/05-2/5/05 and 2/10/05-2/12/05. the number of rooms available at these rates are limited."
I remember that many folks still got the discount even though it showed blackout times. I had my entire trip discounted, but did not have an AP discount, I had an CM discount.