I wouldn't got that drastic to not allowing modified files, like the man said, they are normally mods like FFUR etc.
But I DO think they should so something about these "1337 h4x0rZ" in OFP and Armed Assault. It would ruin the game entirely, I mean look at what happand to BF2, they arn't using Artillery anymore, its more like Cartillery where they just shoot hummer after hummer out of the sky and onto the ground, I do not want this happaning with armed assault.
Without a decent anti-cheating program it will ruin Armed Assault entirely.