All GameStops participating got an email regarding the new distribution cart in mid January, and got the carts by the end of January. They knew about the new cartridge a month before the GAMESTP was set to distribute, and had the WIN2011 carts before the Mall Tour.
The thing is, Nintendo never intended for the Distribution DS's date to be changed, so it was never intended to be released after they changed plans. Someone had to force the Distro Cart to distribute the Celebi, by toying with the date. Which means 'cheating the system' was necessary to make it distribute in the first place. They aren't authorized to change the date on the DS in the first place!