I am under the impression that job descriptions and what they are allowed to do as part of their job is constrained for union workers. As a form of protection,

I am under the impression that job descriptions and what they are allowed to do as part of their job is constrained for union workers. As a form of protection, this makes sense, so that you can't be forced to do work that you aren't being paid for, like repairing equipment. This has both upsides and downsides and I have heard that sometimes it is taken to extremes.