Thank you for your detailed feedback, Alan. The primary purpose of the tarp sheet is for those who need to load the horse muck, leaves, etc, into another vehicle, such as a road-legal muck trailer with no ramps onto it. The tarp allows you to unload the muck next to this trailer while keeping your grass / hardstand clean, while you shovel the muck into the trailer. Swivel wheels have many pros but a few cons, as described, and I have relayed your feedback to the engineers. When used offroad and on paddocks, no wobble should be felt. The main benefit is the ease of turning and manually maneuvering into storage. Without a second set of wheels, there will be too much weight on your vehicle's towbar, and without the swivel function, it would be near-impossible to maneuver the machine. Thank you again. We are glad you are happy with the EBP's paddock cleaning ability!