I certainly do, I got thrown off mine when an impatient bus driver beeped his horn behind me, I was dragged over the road with my foot caught in the stirrup. A car who thankfully managed to stop in time was being driven by a doctor who said he was surprised I was still concious. I broke my arm, dislocated my shoulder and cracked 4 ribs not to mention numerous cuts and bruises. To my credit, I feel, I managed to get up, cross the road get ont he bus and give the driver a very offensive piece of my mind!