I caught this fellow wallhacking on our server the other day. Evidence:

https://www.youtube.com/watch?v=hXIcGvT74aM

As you can see, he is quite clearly following people's movements through walls. He is constantly looking at walls instead of corners as he moves around, and at 2:18 you can even see him trying to shoot someone through the container. At the end of the video I confront him and, as you can tell, he claims innocence but immediately leaves the server (at 3:59) as it becomes clear to him what I am getting at.

(At 2:40 the audio disappears because I tabbed out of the game to take a look at something.)

https://bf4db.com/forum/thread/atollix-5123