Fraternity guys will likely know you are in a sorority b/c they remember your face from a Greek event, a mixer, a date/crush party, a formal, etc, or they even remember seeing you in your letters previously (like in class or something). Guys can spread rumors just as quickly as girls can about things they saw other people do (especially at parties).
We are representing our particular GLO in EVERYTHING we do, letters on or not. In class, on campus, at work, at parties, at clubs/bars, at a store, while driving our cars (think GLO-related stickers/tags), or any other place imagineable, we are representing our GLOs.
You never know who's watching. The person you flicked off at the intersection yesterday could be an alumnae of your organization, a professor you'll have next semester, or one of your fraternity bros'/sorority sisters' parents.
