Normally the home team wears darker unis. The road team wears white or another light color. (Games at LSU flip that; it’s their tradition.) Switching from that requires both teams to agree. Tulane didn’t ask to wear white until August 17, although this game has been scheduled for close to 10 years.
I thought the home team got the choice.
I recall Tennessee wanting to wear black and orange for Halloween a few years ago. South Carolina went along with it.