Breakage: Yep. Loaned it to a friend who tied onto a sled that was actually hung up on a tree trunk we couldn't see. When he hit the end with his machine, the stuck sled didn't budge. The pulling sled had lots of traction, and the bunje broke.
Safety: yep, keep your helmets on and hide however you can. We had two bunjies and a rope on a sled down over a hill crest, and the rig came off the stuck sled. Rig came flying up over the hill and about nailed the driver of the pulling sled as well as bystanders.
Getting out by your self without an anchor: I heard of this, certainly wouldn't do it on a hillside, a ledge or a creek: Get a small S hook. Tie parachute court to one end, close the end. Drill a hole in the throttle lever in which the open end of the S hook can be inserted. Do all the digging, stomping etc. Hook the S hook through the throttle lever hole, lay out the cord along right ski, grab the ski loop and the cord, jerk the ski and pull gently on the string.... Any takers?