Is that typical of sorority girls?

Last semester I tagged along to some frat party with my roomate who was rushing. Party was fun and all, but at some point some female who I umed was the president of one of the sororities attending the party came and said to me that if I wasn't nice/kind to her she would tell the president of the fraternity who had organized the party to not let me join (I had no intention to join but I didn't tell her that...). I just smiled and went my own way wondering what just happened. When I told that to my roomate he just said that she was probably just trying to get into my pants... Is he right or was she on some kind of power trip knowing it was rush week and just wanted to order me around? I'm new to the whole americant college student life. Is that kind of behavior typical of sorority girls?