I don’t really buy this. I take it you’re worried about vengeful ex-employees abusing their access privileges to break stuff on the way out?
It seems like a self-fulfilling prophecy. Probably some people would feel vengeful if you do shitty things to them like removing all their access and firing them with no notice whatsoever.
Bad employees can already break stuff while they’re employed. They might feel more inclined to do stuff like that if there are chilling effects that build distrust in the work environment, like jump-scare layoffs.
Conversely, if people are getting “fantastic severance” and you treat them with dignity on the way out, aren’t both they and the people who remain more likely to feel more positively inclined?