From what I understand, schools do not know what other schools you interview at. At every interview I have been on so far, they have either asked what other schools I interviewed at, or we were asked to write it on a survey sheet. I am pretty sure that all information is confidential, especially before Dec 1. I was told at one school, that once Dec 1 rolls around and acceptances are sent out, other schools know where you were accpeted. I was told this does not affect a school's decision to accept you, but, if you have a deposit already paid at 3 schools, no other schools will accept you.
Anyone can correct me if I am wrong, but that is what I was told at one of the schools. Best of luck on your interviews and maybe I'll see you at NSU!!! 🙂