For the life of me I couldn't seem to kill anyone granted I haven't played a MP PC FPS in years so my mouse skills are likely very rusty but I kept getting killed by people that would headshot me with out even seeing me across the map hip firing a machine gun. I would also get sniped in the head by snipers across the map constantly like it was nothing.
I experieanced 3 people that were doing this during the 30 minutes I played online. These people would usually go 20 - 3 or 30 - 2 depending on the map while everyone else in the room was negative or only slightly positive?
The people who were hip firing across the map and getting head shots with out even seeing me on the screen were very suspcious. The sniper was as well but due to the distance the kill cam only showed the bullet so I couldn't tell were they were or if they really even saw me. Which I doubt.