There is a video on YouTube, for which I unfortunately cannot find the link at the moment (if anyone can provide I would be grateful, it may have been taken down), where someone is basically showing how the "aimlock" hack works. It's a keybind that you press, and when tapped, it glides your crosshair towards the nearest opponent. If you press the key for longer, it eventually locks on, and it doesn't necessarily have to lock onto a head or anything like that.
In this video, he uses original footage of himself using the hack on bots, and then compares it to a clip of Flusha on Cache, and it is extremely convincing. It explains the mechanism behind most Flusha aimlock clips, as well as the mechanism behind both Shox's aimlock here, and NBK's little aimlock during the same match against Cloud9.
Basically, multiple pros are using this aimkey hack to locate nearby opponents. They press they aimkey while they are already moving their crosshair in a natural, sweeping motion so that it does not look suspicious, but as we can see from clips that have surfaced, sometimes they are not always successful in keeping the aimlock hidden.
Furthermore, there was a blog by Deathwatcher a couple days ago that provided a technical explanation for why Shox's crosshair freaked out and looks so weird in the above clip. It has something to do with the way wooden doors are handled by this hack-- they fail the visibility check, which is why Shox's aimbot malfunctions and locks onto Shroud through the door. Notice how it doesn't "unstick" until Shox moves behind the concrete pillar?
This is 99% evidence of professional cheating at a major LAN event. It is probably the best evidence the public has ever seen. The clip has been sent to ESEA, ESL, and Valve, so I guess the only thing to do is ignore the trolls/flamers and hope for Vaccening 2.0.