Mine lastest happened a couple of days ago. I'd hauled a wagon load of wood to the woodpile and went to put my 3pt splitter on the tractor. I was thinking to myself how simple it was to mount with my little dollie. In a moment of brilliance, I decided it was a short trip and my neat adjustable sway bars would hold the splitter in place on the hitch pins - wouldn't want to waste 10 seconds to get the Lynch pins out of the tool box.
As I as just a few feet outside the barn, I heard a loud noise and immediately stopped. Good thing I did. One of the 3pt arms had slipped off the pin and that side and the I-beam had fallen to the ground, twisting the frame so one leg was jammed into the right rear. I happened with enough force to bend the top adjustable link. Luckily, nothing else on the tractor was hurt. I couldn't discounted the other side or move the tractor forward. I was able to man-handle the splitter I-beam to the ground (it tilts, so I just pulled one pin), but still couldn't move the frame. I finally disassembled (unbolted) the leg that was smashing the tire.
Once I got the frame reassemblied and back on the tractor, I tried to re-mount the I-beam. I couldn't lift it. I finally took the base off the tractor, lifted the beam with the front-end loader and attached it to the base. Backed the tractor up and inserted the pins this time. The splitting didn't take as long as it took to get from the house to the barn (about an hour). I won't repeat that trip again. The leg on the splitter needs to be straightened and I'll replace the top link at some point. I was lucky I didn't ruin a tire, break the 3pt hitch or do more damage - all for saving a few seconds.