We are probably all little people here, and nothing like this would ever happen, but say you were high profile enough like that Google self-driving guy that Uber poached, and there was a lawsuit - anything you did on that computer would be up for grabs. All your personal projects, documentation, DMs.. it would be super messy. I’m pretty sure companies like having this kind of situation because it gives them legal ammo in the rare case where there is an action.