There is no such thing as black hat that cannot go wrong, especially when talking about Google AdWords/AdSense. They have some of the smartest Internet engineers in the world working to uncover, detect, and deal with black hat methods. I'm not saying BH methods are worthless (they can be quite lucrative), nor that your method won't make it difficult for the Big G to detect. However, using BH methods with Google programs runs the risk of detection and ban. Stating otherwise is either naive or deceptive.
On the method question, if you are going to specify no refunds then you have to expect a few questions like that. Why should I, as a potential buyer, just blindly trust that this isn't just yet another rehash of one of the couple common AdSense BH tricks?