One day her son came home from school with bruises on his face. Before going to bed he asked her "Mummy, are we bad people?". Shocked, she replied "No, why?". Boys at her sons school had seen her driving on Facebook and had taken it upon themselves to beat up her son. There's no actual law against women driving in Saudi Arabia and yet it's forbidden. Two years ago, Manal al-Sharif decided to encourage women to drive by doing so -- and filming herself for YouTube. Hear her story of what happened next.