What does that mean, I have been on hiring committees before but don't even know what it would mean to "blacklist" someone. If you just mean not hire them at your company in the future I think the candidate will be fine with that. If you mean across many orgs then... Do recruiters and HR people have some secret club I don't know about?
I've also been hiring before and if my colleague told me he had a list of people he didn't want hired because they didn't write him back, I'd laugh my ass off and continue on with my day.
