As you can see in this video.. hes doing it since 4ever .. youtube.com/watch?v=bTrGhLz-Pmg
Everyone knows, but if nothing is detected, theres nothing wrong... theres no cheaters in CS if they dont get banned. VAC is a state-of-the-art of anti-cheating as said by Valve.
if you zigzag quick enough it feels like a downward pull but with more friction. Its kinda hard to explain you need to get the feel for it. But obviously you wont be spraying people from distances and for many bullets so thats where Kjaerbye's aim comes.