Living and working in the mountains, I am always concerned about runaways. Working on steep ground--which is what I do most days--if a log or a round gets away it can have catastrophic consequences. I flicked a little chunk loose one day last week thinking it would stop somewhere on the hill below me, and my help told me later that it continued downhill and catapulted across the road before landing in the creek. Luckily no traffic at the critical moment.
Several years back I was removing a tree next to a house on severely steep ground. Before bucking the tree into rounds, I took a bunch of limbs and made a fence below me to catch anything in case something rolled free. Sure enough, one round got loose--but it took a bounce and flew over my "fence." My heart was in my mouth as this heavy round hurtled downhill for a long ways headed for a house down the road. I figured the round probably weighed maybe 50 lbs., but with its momentum it could've crashed through a window--probably through a wall--and could kill someone inside. I was lucky on two counts--the round bounced around and came to a stop in the driveway outside the house, and no one appeared to be home when I picked it up after finishing the job. I took that round home and weighed it out of curiosity--76 lbs. With its momentum, flying downhill, it had murderous potential.