[pTK]

I would like to point something out. When I used to hack, I would sometimes purposefully ran past enemies if I thought it might be blatant if I shot them, but other times I would make shots that I shouldn't of known to make. My point being, non-blatant hackers do miss things every now and again to try and throw people off. That doesn't mean this guys guilty right away, its just something to think about. A good way to make someone even more blatant would be to piss them off. Start talking trash to them calling them bad. They'll be more inclined to do ****** blatant shit that will give them away just so they can kill you and "teach you your place". 

As to the demo. He peeks things he shouldn't peek,(Better yet that he doesn't peek every round only rounds that there actually is somebody there).

My vote,  Using some sort of walls. I'm not in the mood to speculate the exact nature, but i'm sure he is using some type of hack that allows him to know the whereabouts of enemies.    I vote Guilty.

Also the way this guy is pleading his case doesn't feel right.

He makes a statement

"2. i would be caught by the VAC protection thing way before I would ever reach 8k."

That is one of the most common used phrases by hackers.    "IF I HACKED THEN VAC WOULD HAVE CAUGHT ME"   
Lets be serious, if VAC caught everyone that hacked then there wouldn't be a problem with hackers. You don't need to know anything about the game to know that, that's just deductions skills.