I honestly think the main reason PNMs are not told the "full truth" about recruitment is to encourage them to actually go through with it and do it without fear. If they knew all the dirty details (the cuts, the drops, the percentages) more girls would probably back out from the beginning.
Then again, I think it depends so much on the school you go to. At my school recruitment was SUPER competitive and I definitely felt like the "mutual selection" thing was a little sugarcoated to encourage people to stick it out. A lot of really great girls in my rush group were cut right off the bat
They would have been wonderful sisters!
I had very good friends in several houses and had AMAZING conversations but was still cut from those chapters. At the same time, I had mediocre conversations at several chapters that seemed uninterested in me but I kept getting invited back to them and was even preffed at a house I felt no connection with at all. So I agree, it's not 100% mutual, and I do think "mutual" is a misleading term. More or less (at least from my experience, I could be wrong though) the GLOs choose you and you either go along with it and enjoy or drop out.
Of course recruitment is so complicated and it's basically impossible to give everyone A) a bid and B) what they want, especially at large schools with competitive rushes.