It doesnt work. Fact. The disc brake relys on having two smooth surfaces. Friction is heat, the heat comes from two surfaces rubbing. You are correct when you say something that increases the friction will improove the braking, but in this case it doesnot. By grinding the disc you are reducing the surface area which the pad can use to slow you down. Trust me, it will not work, unless you use soft pads which can compress into all the little ridges created by doing the grind. And since these do not exist...