Other mistake: In the scene showing Fletcher hanging over the wreckage of an anti-aircraft gun after he was speared, the camera flies up above the gun looking directly down the barrel. The plug welded into the barrel to deactivate the gun under Australian gun legislation can be seen.
Other mistake: The stirrups on the horse that Nullah (the young aboriginal boy) finds at the beginning of the movie are perfectly adjusted to his leg length, even though the previous rider was an adult.
Other mistake: The union jack being raised at the beginning of the movie is actually being raised up-side-down - a very common error. Wide white band must be uppermost near the pole.
Other mistake: When Nullah rides the horse out of the billabong at the beginning and is galloping towards the ranch, you can see dust rising from the ground in front of him from another horse and rider.
Other mistake: When Nullah rides the murdered Boss's horse to the station ranchhouse, he arrives at the hitching post with one rein already tied to the post. (00:03:45)
Answer: So they'd be unable to water their cattle. Which has two benefits for Fletcher. The first being that they'd have to take their cattle to the watering hole on the border of their property, making it easier for Fletcher to steal the cows. Second, and more long term, their cattle would be of poorer quality due to lack of proper care. The ranch would lose money as a result, and they'd be more amenable to selling the ranch to their competition, whom Fletcher works for.
Phixius ★