Property ownership.
Those agreements are only good for what you can defend.
Witness the Israeli settlements. The Palestinians can't defend their land against the Israeli Army, so the Israelis take it.
I can't imagine some company staking out a "claim", and being able to do anything about someone else coming alone if the company couldn't physically defend the property.
And if they could defend the property, they probably wouldn't need the "claim".
Might work if a government were willing to fight here over property owned there.
Arf