I'm working on a server side fog enforcement variable patch for bzflag-2.1.10. If _fogEnforce is true then the client can not turn fog off. Still can change between fast and nice. If fog is turned off when the player joins fogEffect is set to fast. This allows fog as part of the gameplay. I have created a couple of maps that rely on fog. This would, of course, be the server admin/map maker's decision whether or not to enforce fog. If _fogEnforce is false then the client has complete control over fog as is now done.
Could this be worked into the new 2.2 version? I have a working patch.