The mill, most obviously, presided over the working life of the town. They supplied most of the jobs in Fries, and owned the properties on which many of the other establishments in the area operated, giving them a certain influence over these jobs as well. It was a desirable place to ork for many, as the application letters demonstrate, and employee appreciation was a part of the business model.
The mill was a desirable place to work, but they also had to be wary of poachers, who would convince mill employees to quit in order to gain skilled workers for their own companies. It is clear that the mill felt entitled to the labor of these people, and so took steps to prevent their being convinced to leave.