The mikvah ladies who volunteer in Rabbi Abadi's mikvah have intensive training. They are told one thing "make sure her hair goes down". The only time I corrected someone was when she confused the Yehe Razton with Tefillas Haderech!
My neighbor gets called from different cities to give a 3 day training course in how to be a mikvah lady. It's scary to think what goes on in those sessions.