we had several leeeeengthy threads about this in the past - and it is still the same thing:
some idiots need their epeen and try to "win" by using flat vegetation (very clear on that battle map with the huge grass - a certain cav player is ALWAYS lancing in there with pinpoint accuracy where he shouldn't be able to see shit...), transparent walls, rain/fog removal, etc.
As long range archer it is your job to take up firing positions with good cover - and after some time you realize: there is no such thing in c-rpg, because around 30% of the players across all classes are using one or more cheats of this sort.
This has been known for a long time, AFAIK it would be easy to fix (make list of allowed mods or integrate them into the official release, check file integrity at every launch), but obviously nobody has ever seen the need for it, "cuz fuck realism".
Of course a file check CAN be circumvented, but that is way harder than just editing a couple of files, and would reduce this sort of nonsense.
Way better than leave it to (never biased and never brocoding and never otherwise "not so objective") admins...