don't know if the ban only is on an account or IP ban or how it is but you can only be banned by being reported. Punkbuster only kicks the hackers from the servers but do not ban. If you use an hack to much will know that you are hacking (like if you keep killing stealthed people when you are on the other side of the map) and hacks will be detected but when that happens a new hack or a new version of the hack will come out^^