cob

All of the sororities do except the top tier ones ie. tridelt theta chi o adpi

This isn't true. These sororities will do cob occasionally too. They just do it under the radar. If girls they recruit drop they have to replace them. These sororities have very few girls drop. They usually take girls they already know. Their cob isn't open to everyone and you won't hear about it. I personally know a girl who did cob for adpi and tri delt

I am a tridelt and I know for a fact we did not take any cob girls. I don't know about ADPi but I also know for a fact chi o and theta never have done cob in any case

you can only cob if you are below total. even if you lose girls out of your pledge class, some of the chapters will still be above total and can't go out and get girls to replace the ones they lost.

they might not have a choice. most national organizations require you to be at total if you want to be eligible for national awards. not being at total only hurts the chapter, there is no benefit to staying below total.

Most chapters, even the top tier ones can't afford to lose many girls. It's not difficult to go below chapter total. Especially since a lot of sororities tend to have their members drop by their senior year because they become uninvolved. Not participating in cob because you are "too good" would result in heavy fines from nationals. My sorority took a couple members through cob and I didn't even know about it for a while afterwards because they initiated with our regular pledge class. Just because the website doesn't list them as doing cob doesn't mean it doesn't happen. Even members don't always know about it in their own chapter.

'hello' doesn't know what they are talking about. Every chapter loses girls for various reasons, grades, money, time, loss of interest, kicked out for disciplinary reasons, transfer, graduation...you get the picture. If you drop below TOTAL then you have to replace those members. End of story.

If that were true then your chapter had to pay a fine. But I doubt you would have known that information since most at meetings most sororities don't announce they're one under chapter total