I have been VAC banned from Black Ops 2. I have posted a ticket asking why I have been banned, but I think I know what the reply will be. The only hack/cheat I have used is this external crosshair, so I advise anyone downloading this not to use it in Black Ops 2 and that the risk of being banned for using it in any game is now real. I haven't received an answer for the ticket confirming that this external crosshair is what got me banned, so I cannot say definitively that it is detected. The version of external crosshair is v3, currently the same version as the one here for download.
I will post a comment later after I have received an answer to tell you if it was this external crosshair that got me banned.