ZTAmazing - my daughter is the social chair for her sorority (actually taking care of her last official social chair duty as we speak), so please understand that is my only frame of reference for what I am about to say.
To anyone on this forum, please feel free to step in and correct me if I say anyting out of bounds.
First, I feel like we aren't hearing the whole story. I can't think of many people in a sorority or in college for that matter who don't want to get out and meet new people. Particularly if they are freshman.
I understand that in any group there are some people who are naturally introverted, have steady boyfriends they are with 24/7, are double major in nuclear physics/micro biology, or are seniors who are partied out and just ready to be done with the whole thing, but unless you are in a sorority of 20 girls (maybe that's the case), the people who fit one of these categories shouldn't be a big enough group to affect you reputation.
Given that - I would figure out whether or not they don't like be socialble at all or they just don't like the sorority socials. Some possible reasons have been mentioned here, but the only way you are going to know is to ask. First thing daughter did as social chair was ask girls what they wanted to do and with whom.
Having said that, I know hers, like some of the ones mentioned here, gives points for coming to social events and it gives more to those who may not want to go for some reason and volunteer to stay at the house for girls who are uhmm... sent home. It isn't normally an issue- most girls want to come, but it is a motivator for the ones that ride the fence.
To HQWest -I think your point is valid and it is something the OP should consider, but I don't see why ALL events should be either with a specific fraternity or bring your own date (maybe I'm misunderstanding you). On her campus (and all the others in our area she knows about) they mix up the types of events - some you bring a date (whomever you want) and some are with specific fraternities. She tried to make sure they never did something with the same fraternity more than twice, so they did things with almost everyone's "favorite" at least once.
Otherwise I would agree with what 33girl said - Daughter has had a BF almost the entire time she's been in her sorority. He is in a fraternity. Some things they could go to with each other - some things they had to do separately. Going to a party for a couple of hours, meeting people, hanging out with her sisters, and then meeting up with him worked fine. Her reason for joining a sorority was to meet people and hopefully make some lifelong friendships. If she had refused to ever go anywhere with her sisters because her boyfriend couldn't go - she would have exactly one friend now - her boyfriend.
Oh, and 33girl - never fear - Bid Day parties are alive and well on her campus. They are (a week to a month) after the actual bid day and bid day activities- which are dry of course. They do them with a specific fraternity or two and yes, it is a party. Where there is a will, they'll find a way.
