You can't really lump maps and mods into the same category as skins and models. Everyone plays by the same circumstances in the same mods and on the same maps. Modifying skins and weapons, particularly player skins, changes the game, and changes the circumstances. More than a few people on IBIS have played with red/blue skins, and too many members of the community have displayed interpretations of fairness disqualifying them from any notion of trustworthiness.