This guy lost it on an off-ramp almost exactly a year ago.
Thread. There was also an Australian or New Zealander who lost control and drove over a cliff a while back (can't find that one), and a trailer-induced rollover (also Down Under):
About a month ago I had the misfortune to have what could have been a serious (I mean serious) accident on the road from Wisemans Ferry to Mangrove Mountain. I was followed by a friend all the way, and at Spencer, where we stopped for coffee Len made a comment on how well the trailer I was towing was travelling. Not ten minutes later, as I rounded a series of bends, at relatively low speeds, I had my accident. It happened so quickly that I don't even recall what happened, and how it happened.
I found myself lying on my back with the Spyder on top of me - upside down, the trailer still hitched to the towbar, and lying on its side, with all the contents spilt on the roadway. I was helped to my feet, and it took a little while to comprehend what had happened. Somehow, the Spyder was thrown onto its right side, then bounced back to its left side, then rolled over.
Both mudguards had scratches on it, the windscreen was smashed, and the tacho/speedo cluster had fallen out. The left hand mirror was snapped off, and the rear left footrest bracket had snapped. The Spyder was pulled back onto its wheels, and once the speedo cluster was reinserted, it was able to be started, and eventually ridden back to Sydney. The trailer however, had to be put onto a towtruck as the towbar was damaged. For some days I was in a lot of pain, and after going to hospital, was told I had a fractured pelvis with subcutaceous haematosis (bleeding under the skin).
When at last I was able to bend, and lift, I did an autopsy on the trailer. I removed the body of the trailer from the chassis to confirm what I had suspected - at some time (the trailer was about 10 years old) I had ridden over a pothole / rock / bump which had been so severe that the floor of the trailer was torn. The chassis frame directly underneath had metal fatigue and cracks in the welding. So every time I went over another bump, not only was the damage spreading, but the mounting bolts were tearing through, until there would have been only a couple of bolts on one side holding the trailer onto the chassis.
That one right hand bend was enough to lift the body off the chassis, pass the centre of gravity (point of no return), cause the trailer to then roll, which then pulled the Spyder over. The shape of the Spyder, and the topbox saved me. This could have very easily have happened whilst towing with my previous bike - a BMW. I shudder to think what would have happened if it had been anything other than a Spyder. I walked away, and was able to ride home.
What I learned from this, I have passed on to others - we do checks on our mounts, but how often do we check our trailers? Three of my friends who also have trailer, have since, checked their trailers and found that similar failings were found. Trailer floors have carpets, gear, that can hide the true condition of the trailer.