My son was at a friend of mines. She asked him if he would like to ride one of her atv's. She has property in her backyard, where she said he could ride at. She also has built a ramp that was covered in tall grass and weeds. So while my son was riding the atv, he went over the ramp he did not see, and broke his collar bone. She didn't inform him about the ramp she had built, but insisted he should ride the atv. She is now telling me to pay for the damages done to her atv, but should she be paying me for my son breaking his collar bone on her atv ?