I think if you are going to have a rule about not drinking in letters-fine. If everyone knows about it and agrees to it-then enforce it. But make it all letters. One sorority on my campus is not allowed to drink in letters but can in a formal T-shirt? "Letters" is defined as BIG letters on a jersey or in your pin (Which is even harder to see in a dark bar than the XYZ Crush Party in neon on your t-shirt). A socia/rush/formal t-shirt doesn't count as letters. Now that is just stupid. Letters are letters are letters. But really, anyone not greek or who doesn't know you doesn't give a crap what you do in or out of letters. If you are acting like a lady-thats what they'll think. If you are acting like a ho-thats what they'll think. And anyone who does know your letters or is greek, knows you anyway so it doesn't matter if you have on letters or not. They're paid for. Might as well wear um! ***Side note: a couple of buddies of mine actually have a running joke in their frat that if you have on letters-you are required to be holding a beer. Kinda funny.