A decade or so ago...
I was a permie in a company which was looking to cut costs. One of the ways of accomplishing this was to swap out contractors for permies, so when my CV popped up in the internal HR system as available, the manager of a team with a contractor on it saw an opportunity to meet one of his annual performance goals.
So, we had a nice little telephone interview and he arranged all the HR paperwork, etc.
However, he didn't actually get around to informing the contractor until the day that I physically arrived in the office. And the contractor had been with the team for the best part of a decade!
As a result, the contractor felt stitched up; he did two weeks handover and then dropped out of sight, and I was essentially left as the team pariah.
I don't particularly blame the team or the contractor - and to be fair to the manager who triggered all of this, he was a reasonably good manager for the year that I stayed in that role before deciding that I'd had enough.
I just really wish he'd had the courage to talk to the team and contractor at some point during the month before I started the role!