Arma 2 detects it via the Key and then you become a one hit kill.
I want to throw in another method:
Make an extra torrent version.
Like giving your actors in the game a piratehat or anything else that is just cute and funny.
Then cut down the playtime and distribute it to the torrent network as official release by some unknown hacker group.
Advantage is clearly more free attention for your game if it is good and the pirate hats might cause a lulz or two which is always good.