It’s not that it’s not allowed but it’s not required. Labor market is very unequal in information on one hand, where it’s much harder for individuals to know what is their value for the business and how are they doing versus the peers. Then there is strong arming through credit obligations and work + commute time that effectively makes it very prohibitive for people to object.

And so since you can exploit the people, most businesses will. That’s a very easy way to improve your business results.