I was running along the edge of the map with the intel in hallway and was looking straight in their direction (diagonally away from the map edge) when they got a headshot on me. They appeared out of the fog a second later. I asked them how the hell they homed right in on me out in the middle of nowhere, and they replied:
You know when sniping, the horizon becomes white. Those white stuff is fog. No fog hack removes the fog which reveals the horizon and some camping spots.