My sister transfered after being initiated, but it had nothing to do with not wanting to be with her original sisters. In fact, a year after she joined, the chapter was closed (small numbers or something like that). She decided to try to reaffiliate with another chapter after she transfered schools. They couldn't allow her to, because of the total chapter limits in place or something like that(this was at a large, southern state university).
It's at this same university that I rushed my freshman year. Out of my rush group, 5 out of 25 girls ended up getting bids. The rest of us ended up dropping out.
I think that most people don't fully realize the pressure that is put on girls who rush at the larger state universities, especially those in the southern United States. There are not nearly enough spots available, sometimes not even HALF the number. I'm not saying it's right to initiate at a smaller college and then transfer, but I can see how they think it is the easy way out. In my opinion, most of the larger state universities need more sororities, but that's just my two cents.