My sorority, Gamma Sigma Sigma, is a little different.
*thinking of a PC way to put this*
I've been in GSS for 5 years, and what I have noticed is that our chapters which are predominantly AA will wear NOTHING but Maroon and White, our colors. I pledged at a chapter like this. My shirts/line jackets only come in black, white, khaki, or maroon with the maroon and white letters, or vice versa. Like abaci said, though, that doesn't mean my naila isn't creative--I have stuff with either white roses or penguins all over it
Now other chapters of GSS that are not predominantly AA have GSS letters shirts of all colors, the letters are all colors. It's for the same reasons many of you have already listed--the "family" colors you guys talked about. When I first saw it I didn't understand it. And my sisters didn't understand why I wore maroon and white all of the time either
All I could say is, "Well, this is how my chapter does it"