It has happened although it's probably a "man bites dog" sort of thing that made it into the news.
I'm not sure it's good policy in general to discourage people from working--especially in the area they presumably have some expertise in.
Back when it was allowed, some companies would pay in fake company money called "scrip" that you could only use in their company store to buy food. They also owned the houses so you could only rent if you were an employee. Wanna quit your job? Good luck also losing your house and not having actual money to go anywhere else.
You gotta understand that if you have something that can be abused for profits, then it will be abused for profit. Even if a company is has a heart of gold and decides not to do this, they will be out-competed by companies who are willing to do evil things and thus be more profitable. Abuse will happen by logical necessity.