I...understand what you are saying about the colors...but you have to realize...that 'pink and green' are the colors for this year. And it used to be if you were interested in an organization, you didn't wear those colors together...however, it wasn't a 'rule'. At any rate, you may see a lot of people with those colors on. You shouldn't just assume someone is a 'soror' because of that.
That's just my take on it. Our colors are pretty nice
...I've even caught my Delta friends in such (just as they have caught me sporting 'red and white' before.
Now if the shirt had 'AKA' or 'Alpha Kappa Alpha Sorority, Inc.' written across it...it would have been a whooooole different story.
Just my .08 cents...