To effectively combat cheating, the server must be made to check certain things, especially such things that should be impossible. For example: the heaviest weapon in the game is the laser guided bomb of the Harrier, with a damage of 5000 Â and an explosion radius of 15 meters.[..]
You mixed up two different things here!
One is mentioned by Anth and partly could only be checked by the client itself because not everything is transmitted to the server such as the breathing thing or if your grass is there or not... These things can only be stopped via client side checks!!!
On the other hand there are these addon "hacks" which AT THE MOMENT let you be a super warrior with super weapons and some other shit.
BUT this has already been encountered by the signature system!!! The only problem is that currently the system is unusable because of corrupted signatures provided with the game and the non published signature tool. But if we are able to use this at the end it is the most secure system against addon hacks like shooting bombs or change configs!!!!
The "only" problem which is left then are the client side 3rd party Hacks (wallhack etc. outside of arma)...