People you don't want as sisters

[CutiePie2000]

I think that Carnation makes a very good point.
After all, if you were an employer, you would not want an employee who was going to cause problems, and you would never hire someone without making sure that their references checked out first. Similarly, I don't think membership in a sorority is all that different...you want to make sure someone will be an asset to your organization, not a liability.