There have been several account of Animal Crossing: City Folk being sold before the release date, including my own! I saw on another website that a woman had purchased her copy on November 11th, and thought I would give it a shot, considering I needed to run out for some errands anyway. Lo and behold, a single copy sat on the top shelf of the Wii case. I asked an associate to get it out for me, and purchased it before informing them of their mistake. The salesman [with a 20+ years of service badge] then said he didn't really care and that if they were making a mistake, the computer would have told them so.
Check the forums for pictures.