Originally Posted by Raggz

The use the same way as MS uses to ban hacked xboxes. They gather data ,flag the users and then ban them in waves. And Steams policy is the same. You will never get the account re-opened no matter how high you cry or whatever threats you can come up with. Not as long as you did cheat or use any mods in multi-player!
Better think twice before doing any of these things unless you don't care.