One of the rules is that the horse can NOT have any leg protection. They expect a good trail horse to be able to take care of his legs.
So I've saw many a weekend with 100 horses head out across Colorado or Utah terrain with no leg protection. And some how those horses all survived.
Two weeks ago I rode into Utah's Robbers Roost, ( you can see the other thread) About 20 folks along into some of the most remote country in the west. No trails, We just bushwacked it where we needed to go to cross the canyons and ridges. Again, Not one horse had any leg protection. And again everybody made a safe couple days of riding.
If you can't tell, My personal opinion is that is over kill for open riding, Maybe running barrels or cutting cows where you have lots of laterial movement, But not needed on the trail.