Brothers dardenr and pirate00, I had things like that happen to me too...
Most of the time people will think I'm a member of Delta Sigma Theta because of my letters. I can remember one time I was in my car at a stop light and a woman pulled up next to me (I have a GSS tag on the back of my car). She was like, "Hey Soror!" and I was like, "Oh...hi..." thinking that she may have been a Gamma Sig. She asked me if I was in Delta and I had to say no, but I think we both felt pretty silly
Another time a lot of my sisters and myself were at a Wal-Mart during our National Convention. You know how it is at Wal-Mart: we're just walking around, chillin. Well another young lady that walked by us with her shopping cart WHIPPED around and started back towards us. She came up to us and greeted us, giving us hugs and everything! She said, "I'm in Kappa Sigma chapter at East Carolina" (we're in Greenville)! "Is there something big going on this weekend?" We knew something was up because GSS doesn't even have chapters starting with Kappa yet

So I tell her, "We're in Gamma Sigma Sigma" and she goes, "Oh, I thought you were in DST, my bad!" Sorry to burst your bubble...
I think it's because people just see the Sigma in the middle of my car tag or shirt, or that my sorority's colors are Maroon and White and DST is Crimson and Creme. Another time I had somebody ask me, "What does T-E-E mean"

No sweetie. This is a Gamma and those are two Sigmas.