Employers have a lot of legal flexibility with hires and re-hires. If the employee was a dog the last time, that 10 foot pole looks pretty good. I have had former employees who had good skills but toxic personalities. Of course I am not going to rehire them or "nice guys" who could not do the job the first times.
I had an open AP position once. Well qualified candidate in another department I wanted to give the job to. But then some former employee whose sole qualification is that she looked like a Playboy model wanted the job and my management went crazy. I have never had my boss (the controller) sit in on an interview before. He showed up, the VP Finance showed up, and the COO showed up. The candidate wore a dress which stopped around her navel and showed deep cleavage. I left half way through the interview and no one missed me. My (all women) staff went ballistic until I pushed back hard and told them to go bother the brass. I was told we had hired this person even though we had previously told the inside person the same thing. After 6 weeks of no-shows to the new hire orientation, I was finally allowed to hire the qualified candidate. Whom we had hung out to dry with their old manager.

