> For a trivial example, programmers who are proficient in Emacs not being allowed to install and use Emacs.

I'm not sure how you mean trivial here, but not being able to use emacs isn't a trivial matter to emacs users :)

> I still fail to see why employees will now choose to disregard this particular rule, and either disobey or quit.

I fail to see why employees follow rules that make no sense rather than disobeying or quitting.