Are you sure the fog is actually in the map? My first thought was that they shopped it in for dramatic effect. And take a look at the postcard. No fog there.And look at the sexy ground fog.
Anyone noticed the significant lighting highlight on the sniper? Presuming this is not also a 'shop, do you think this will be an extra compile variable, determining your maps day/night time for added night time player definition? I can't see how that's normal TF2 light rendering, even if it is somewhat "special" with it's 7 lighting layers.