well same as Cheating Death in CS does, thats why its hard to make it run in the background. But I know some1 who has CD-Proof hacks, the means you have to hack the Program (Anticheat). DirectX Hax are detected on Punkbuster. But there are Blockers for it, so you can update it and make it undetected again. As long as you dont share to public, the the hack is undetected.