Last fall a neighbor was using a similar jack to change a front tire on their slightly inclined driveway. Well, they get the lugs off and when taking the wheel off, the car rolls back as they didn't block it, twisting the jack and pinning it, the loose tire jamming between the left front fender arch and the ground. It bent the top of the arch out 3 or 4 inches. But hey, the car stopped rolling and fortunately it wasn't an arm or leg stuck in there. One of them came over and asked for help. I rolled the old Walker over and a HF wheel chock to get them out of their predicament. Their jack was so bent it wouldn't lower at all. With a tire installed and car back on the ground we were able to lean on the wheel arch and move the bend back a little. They never did have it repaired though.