This exact thing kind of happened to me. I bumped the car in front of me in traffic ever so slightly and she said that she was going to have to have the bumper taken off and checked etc etc etc. It all went through insurance as I wasn't prepared that any such damage had been caused. It went on for a year. The insurance company said that she had the car checked by a garage which was reputable to them and as the damage to her car tallied up with where my car had made contact I would have to pay - it was about £368! I said I didn't want my no claims affected so I would pay the £368 out of my own pocket directly to her insurance company. They passed my details on to her insurance company who about 4 months later contacted me and asked for about £218! So my insurance company had completely inflated what was owed. Her insurance company provided me with all the receipts etc so I felt as satisfied as I could do in the end. To be honest I wish I'd hit her at 100mph and then the horrible old cow wouldn't have had the opportunity to have wound me up so much. There really are some cocks on the road. Unfortunately though, if you've made contact with their car then there isn't much you can do to avoid it.