I was Sigma Chi sweetheart in college (awhile ago) and at least for them, it's a little sister type thing. The men were great, so sweet to me, always very respectful, I was kind of an ambassador for the fraternity, attended recruitment events, alumni functions, dinner when national officers were in town, appeared on the composite, went to all formals, etc. It was a lot of fun. Sigma Chi at least also has what they call an International Sweetheart
http://www.sigmachi.org/internationa...t-of-sigma-chi.