This is an interesting discussion as I am getting a bit bore with just traveling and am considering either a job (seasonal) or a Camphost position.
But in my research I have seen that many of the positions on Volunteer.gov. are actually paid a per diem. some as much as $42 per day.
I talked to one set of CH's here in Alaska at a BLM campground who were making more than that.
In other places I note there seems to be no compensation.
But to your point: I don't think you should worry about what the rangers are doing. Just do your job, what you agreed to do and leave them to do what they want. If any one should question why something was left undone simply point out that it was not in your agreement to do that particular task.