The University said LucasFilm wouldn't allow it. However, I wouldn't trust the Ole Miss admin, especially back then. Back when they decided to get rid of Col. Reb about 10 years ago, they held a fan vote among students and alumni. The choices were a black bear, a landshark, and some humanoid looking character called Hotty Toddy. Well, they never released the results of the vote publicly, but my wife was on the student committee back then and Landshark won decisively. The administration didn't care and went with the bear, which was never really embraced and so about 7 or 8 years ago they held a second vote and that was when Ackbar was nominated and won. The admin stuck with the bear claiming that LucasFilm wouldn't allow it. So we really don't know if that's true, but I suspect LucasFilm wouldn't allow it, so the admin was probably being honest about that.