Clients are given only what the server says to tell it, it's part of why I think the system has not been implemented elsewhere. As soon as you add this type of spotting system to anything with faster movement it would create issues. No client has all the information and every action is getting server-checked as the game plays out. It creates a bit of a funny with this because a tree will fall over, and you know a player did it, but the client is not told anything other than "put this tree in XYZ orientation now"
There are no mods to force it to show enemy positions or change the maps. No injection cheats. No wallhacks. No invincible god-mode, flight, or becoming unspottable or flying into/out of the map. No turning a single shot into a laser of damage, or unlimited magazine. No recoil cancel. No getting kicked from session like GTA or mod-menus.