It's not an NPC rule but we have it in my chapter's by-laws which are approved by our HQ. Having it written down takes the guess work out of things because there is a protocal to follow.

The rule is that if a girl rushes and is cut then she cannot be invited to any more rush events for the remaining school year. She is welcome to rush the next school year and could get invited to the first invitational round. That is if the reason she was cut in the first place had to do with being a grade risk. If she got her grades up and kept them there then that looks really good for her. If it was for something else, she won't get invited back.

Why waste time with an unqualified girl? The girl may really, really want to be an XYZ, but if XYZ can't take her, XYZ shouldn't offer a false sense of hope by inviting her to rush events. It can be frustrating for all involved.