Among other reasons:
A Maize Out, if you acknowledge the need for it, should be reserved for important games, like Ohio State or Michigan State, or even this year Nebraska. But because most people do not have a maize/yellow winter coat, any call for a Maize Out pretty much has to come before October 15 here in Michigan. So our Maize Out game is against Minnesota. A team that features, among its colors, gold. And what color does Minnesota want its fans to wear to games?
http://hooverstreetrag.blogspot.com/2011/09/maizeout.html?utm_source=twitterfeed&utm_medium=twitter
I guess ours is not the only "marketing" department that doesn't exactly think these things through.