Ahh no. And Grazing fees is a misnomer.
But I can tell you this IF someone DOESN'T Pay Rent for 20 years but still occupies the land they can lay legal claim to it.
And the government knows this. But any first year law student will tell you if this was just a matter of non-payment of "RENT" then the government would've settled this long ago.
Use your common sense. There is no way the government would allow this to continue for 20 years if it was a matter of non-payment of rent.
It's waaay more complicated than that.