A little girl bumped your car with a shopping trolley right???
Now I love my car more than my own mother, but if I was in your shoes, I'd have just mouthed off to the mother for her attitude, and then found myself a tidy panel beater to sort it out.
theres no need to go through all the hassle, and subsiquent emotional punishment to the little girl of her mother having trouble with the solicitors, court, and all that jazz.
Nobody died at the end of the day, no need for some silly cow's attitude to ruin anybodies day.
avoidance strategy?: park at the far end of the car park, reduces this sort of accident massively, and gets you more exercise.
win win