Regarding stickers and lawsuits, you'd be surprised. I worked for a company that made trailer couplers. We were sued when a trailer with one of our couplers unhooked, crossed into oncoming traffic and killed two people. The coupler, made for a 2 5/8" ball, was on a 2" ball. The trailer had no safety chains and no breakaway brakes and was overloaded. We paid because our coupler did not have a label stating "Do Not Put This Coupler on a 2" Ball".
2007 Damon Daybreak 3060, Ford 16,000# Chassis,
Ford C-Max Hybrid Toad , Suzuki V Strom 1000cc