use sv_cheat on that clip
https://www.youtube.com/watch?v=G47rYU5k2Ho and youd see me do the exact same as him "aiming" at people through the walls. Or this 1
https://www.youtube.com/watch?v=S6rOf24t8Vo
Its called pre positionning your aim by using sound / logic, in my case i had bomb down so i knew they would come toward me pretty fast and heard them. Both times.
In Gabe's case on the clip you made, his upper b teamate and his lower b teamate died and wounded enemies, they could of made calls but upper t side on b is an extremely common spot for t's to go, if its a 5 man rush its bound to have at least 1 going there he heard the jump sound when he was peaking upper went for him, bomb just got downed if there was som1 pit he would be dead by now so naturally checked for lower (if som1 is right side site which he knew there was people they would run into his scope anyway) rest was running around like headless chicken from the start so he knew where some were.
Honestly the fact he never went for the last guy even doh his teamate clearly called him on your clip would indicate that he wasnt cheating at that moment, same goes for the 4th man you can clearly see to his reaction that he was surprised there was someone else there (yeah i got walls but lets reload with only 2 bullets shot ! and run away like a scared cat) =S
+ he called the last guy by saying he was vent to his teamate and played accordingly : teamate went lower b to check b entrance and gabe was looking out for ct / jail sound. But the guy was ninja upper b / pit.
So clearly not enough to ban
at that time.
edit : i'll add that you can clearly see a corpse of a ct jail (mid guy probably), he almost killed both guy site, could of called em, but like the other people b his death alone is a call of where they might be and also if gabe was trying hard, would be a good indicator that they werent pit (since crossing site in low hp to hide in pit is a bit risky when they know ct's are rotating (probably ct / upper ct).