You can't obviously sue a newspaper if it is reporting what someone else has said, and they have evidences he/she said it. Actually, it's also a journalist job to report what some people say.
Ads published on newspapers and TV in many countries are controlled by specific agencies - i.e. ASA in the UK. There are rules about what kind of ads, if any, could be displayed in given hours or type of contents (i.e. children ones) - and misleading ads are not allowed.
Tracking the origin of the ad is quite easy, and if the ad infringes the rules someone is liable.
Biting the hand that feeds IT
