Hacking in competitive CS GO

So, in the America's majorqualifier a team called CHAOS had a pretty strange game against MIBR, and a lot of weird clips of leaf and other players basically aiming through the walls emerged in twitch and youtube.

This is one example:https://youtu.be/7-7H4LsL6Js

What do you think about it? It really was hacking or just coincidence? What the tournment should do?