I was backing out of a dominos parking lt and as I shifted my truck into gear I was jarred forward. I got out asked the woman if her and the children where all right. I then askied if she wanted to file a report. She said no. I gave her my information including insurance also. I am still unclear on who was at fault. When I was jarred forward I looked in my rear view mirror and the reverse lights where on on her vehicle. That makes me question who was at fault. I guess my question is if no report was filed, no witnesses and no proof of who was at fault who would be liable for the damage.( very mild damage to her vehivle and none to my vehicle). Please advise. Thanks