I've never run over myself and have only had two issues while hooking up.
DISTRACTIONS..... and mostly when you stop your process to talk to someone else. That is a prescription to accidents. Once, while hooking up my golf cart trailer behind the Jeep. The neighbor called me over to show me something. I went back and drove the cart up on the trailer. I, at that moment, found out that I had not secured the coupling to the hitch ball. Same thing happened again while loading the cart on the trailer when it was behind my F-250. I'm now shopping for another tailgait. :)