:nuker:Besides the social engineering taking (1) place by cheatmakers, there is also a lot of misinformation out there, or simple knowledge of the subject.
Simply put, VAC detects when someone is cheating on a VAC-protected server (2). This works delayed to catch more cheaters, because otherwise one person could just use one singular account till he finds a way to bypass VAC and then spread it. With it being more unclear what triggered it, and in what time frame, results in more cheaters getting banned and keeps them on their toes.

Of course, due to it being detection based, something has to actually take place before it can be actioned. To compensate for the limitations this brings (both being delayed and detection based), there is Overwatch which doesn't look so much at WHAT someone is cheating with, but IF someone is cheating and gets power to the community to get people banned by simply reporting and peer reviewing (Overwatch FAQ).

So, what more is Valve doing to curb cheating? They've of course Prime, Trust Factor, and many other changes (for example: limits on gifting, and no big sales) that make it harder for recurring accounts to come back and cheat, all the while making it not too hard for new players to come and join the game - which is a careful and delicate balance, because without new blood a game is ultimately just going to die.

They've also taken steps to reduce the ability to cheat, as very simply put the way cheats work is just reading the data that the server sends your client (PC) to make the game work (the positions of enemies) and acting on that. By limiting the amount of data send, or the data that is processed on the server, they've reduced wallhacks and so-called no-spread cheats.

Besides the last (limiting cheats at it's core), ultimately thsoe are just reactionary methods, and they get you in an cat and mouse game with no end. Which brings me to another big step they took, called VACnet (4), which aims at looking at what the cheaters have in common , which is of course cheating and which has some very clear telltales. They are teaching computers to discern the differences of what is possible and thus detect the cheating itself, not the specific cheat used.
:lolo: