Traditional horizontal search engines cannot always identify the target audience niche or vertical industry of a page or site. Vertical search engines address this issue by the nature of their design. They identify sites according to more specific criteria and sometimes even by human input.
People have a moral standard about what they will do and will not do. At the end of the day someone who cheats has a lower moral standard than someone who does not. And they will cheat in other areas of life as well.