Reports of blacklists, official or unofficial, circulate in most professions. Most are probably untrue. Writing for a resume site, a recruiter maintained that there is no blacklist in her field and no need for one. You're more likely to be sunk by a bad interview or an unfavorable reference than by a blacklist. Some people fear a less official form of blacklisting if they have left a previous job under a cloud or made enemies along the way. One way to find out if they're right is for them to run a background check on themselves to see if anything negative pops up. Many web-based services are available to do the job.