Test prep and other types of college admissions assistance are an industry, and they pass referrals back and forth all the time. I believe her when she says she’s read essays (she is an English specialist after all) and that she’s seen the work of essay rewriters.
As far as her claim of a “revolving door” – that application readers frequently wind up in the private college preparation and counseling industry – that’s obvious. Go to almost any college counseling firm website and see how much they will brag about their staff being admissions industry veterans.