Back in the mid-1990s, when I was still working full-time at MegaCorp as a supervisor, we had a re-org which expanded my division's functions and shrunk 2 other division's functions and merged them together. We also added a few workers from those other divisions to compensate us. However, two of our added workers turned out to be their worst ones and both of them, at the time of their next employee review, ended up being put on a 60-day extreme probationary period, kinda like the PIP described here. One of them was in my specific work unit so I was assigned to work with him. I also saw his last performance review (from his old division) and it was the worst one I ever saw.
He was told specifically the things he was doing wrong and what he needed to do to fix them. But in those next 60 days, he kept doing those same things wrong, like he had the words, "Fire me!" taped to his forehead. At the end of his 60 days, I had to recommend to my boss that he be let go. It turned my stomach to have to make a recommendation like that, but I knew it was the right thing to do. I saw the effect his poor work was having on coworkers at his level but could not tell them what we were doing until he was actually told he was being let go and packing his things. He did receive a severance package but because he hadn't been with us for very long it wasn't very big. HR didn't get involved until he was told he was getting fired although they were informed about the extreme probationary period.
The other worker, meanwhile, was also not doing very well. He was in another work unit in my division. He had been with the company for a few years but his problem wasn't being inept so much as being insubordinate. He knew he wasn't go make it through the same extreme probationary period, one he had successfully gotten through once before, I would later learn. But this guy shot himself in the foot when he didn't report to work for 3 days. According to company rules, if someone fails to show up or check in for 3 days, it is considered a resignation so he lost his chance to receive a severance package, one which would have been bigger than my guy's severance package because he was with MegaCorp for several years.
We were also a little concerned this guy, who happened to be black, might try to sue us for discrimination. But because my guy was white and did get fired at the same time, that would blunt a discrimination lawsuit (there was none).
While it was a sad chapter of my career, getting rid of both men did lift a weight off the collective shoulders of everyone in my division.