At my sister's high school, there are no fraternities or sororities (its against school policy) but you have different cliques that want to be greek. For instance, my sister is on the cheerleading team and they ( the cheerleaders) have a call, a hand sign, para, and they get hazed.
Most of them want to be greek in college so I guess that's why this happen. I think if the school allowed it, they would have letters and everything...