My AOII daughter says that in her chapter, they do release girls who keep doing things that are undesirable for the chapter's reputation but they don't take an all-out vote on everyone. I guess it's involuntary depledging, just like we were able to do although we didn't while I was active.
Although one very good sorority at Arkansas released one of the other cheerleaders while I was there... seems she ran stark naked from her boyfriend's car into the sorority house. Too much, even in the wild seventies...