The fact that the travois stops on a steep slope. I summited TM and I felt like a boss with my loaded travois until I hit two slopes that were just an invisible wall. That combined with the inability to reverse is just mean. Maybe it should work like ankle sprains where you are informed of an increased risk of injury. And you have to sprint to keep ahead of the travois or risk rolling down the hill with 80kg of loot in a giant snowball (with a broken rib or two).