Things are done so completely differently here. Rush has a pretty formal setting both semesters, even though the whole pref thing is only done in the spring. So basically, no girl ever has to actually tell a sorority no.
This reminds me of when we ran open bids last semester. We gave one to a girl who went through recruitment but didn't accept any bids. Her polite way of declining our bid was to say she had changed her mind about joining a sorority because she was going to be too busy for one. I'm not stupid, I know she was just trying to let us down nicely, and I was right because she did join another sorority
but at least she was nice about the whole thing.