If I meet a candidate and they haven't used back channels to find out what challenges my team is facing, it's an auto-reject for me. You should at least care enough to do some sleuthing behind the scenes.
If a company expects me to spend my free time doing investigative social engineering work to cut through layers of indirection from a job advert to the interviewer, it's an auto-reject for me. The company should at least care enough about hiring someone to understand that they're selling their team and company "culture" (for lack of a better word) to me as much as I am selling my labour to them.
I guess I would totally not have been hired by you :)
Or they cold-call people at the company, hoping to get the goss. Staff knowing about the candidacy should not respond. Others would hopefully be suspicious - how can you trust staff who tell company problems to any old "candidate"?
Guess you just outright reject 98% of all possible applicants?