Adverse possession is not agreeable possession. If the BLM agreed there would be no dispute.

Levant et couchant means you spent the night and woke up to see the morning sun. This French phrase is generally applied to neighbors domestic animals that come to visit but it applies to the neighbor as well.

Had I been the BLM manager I believe I would have sent Mr Bundy a nice offer which he couldn't refuse ... that his rights to graze were established by long usage but extended to him only during his lifetime. Nothing inheritable in the grazing right. 'Course this would simply be an offer. They seem more intent upon establishing his adverse possession though and have done a fairly good job of providing evidence of it.

Rights are highly transitory. If you fail to assert them then you have none.