I visited Magic Kingdom on Christmas day 2002, and I drove up in my car at 2pm, and they let me in, didn't say a word to me. The parking lot was not completely full, although more full than usual, and when I got to the turnstyles at about 2:15 or 2:30, I was let right in, no signs or castmembers turning people away. I had heard that earlier in the day they had closed for a couple hours, but by sometime early afternoon they were open again. I was in different parks for the few days following, but didn't hear about any more being closed. Maybe just a slower Christmas week? Hope this helps.