We didn't use any Jeep protection for 8 of our full-timing years. We also didn't have the full, stiff across-the-rear mud flap on the motorhome - just flaps behind the tires.
When we spent all summer in Alaska we pulled into a campground in Whitehorse, Yukon and saw a couple motorhome owners taking off their stiff flaps. They invited us to view their windshields and there was a layer of large rock laying at the base. We had absolutely no problems and we had just traveled the same road as they did.