What does a Valve Anti-Cheat (VAC) notification look like?
I'd like to know what messages appear when somebody is cheating and VAC detects it. Do they appear in-game (for games which support VAC natively) or via Steam's game overlay (opened by pressing shift-tab)? Does the game immediately close to show the message? What happens on the screen of the banned player and the players on the same server throughout the whole process?
I couldn't find unmodified screenshots or detailed enough info on google. This post briefly lists the things that trigger a ban, but not how it notifies the user of detected cheating visually.
Best Answer
Caveat: I have never been VAC banned so all information provided below is from different sources across the internet.
When a player on the server is VAC banned
The notification most likely varies slightly from game to game. In Source games, a message will appear in the chat stating something like
Player [PlayerName] has left the game: [VAC Banned from secure server]
You can see this in this screenshot:
Source
(It's fairly blurry sorry, I'm still looking for a better quality picture)
When you are banned
Again, the notification varies slightly from game to game, but if you are VAC-banned mid game, you will get a notification similar to this:
According to the TF2 Wiki, you will recieve the following notification when you try to connect to a VAC-enabled server.

Message displayed to a VAC-banned client.
The TF2 wiki explains in further detail the different measures that take place in the event of a VAC Ban. In addition to receiving the above message:
those who are VAC Banned have all non-purchased items deleted from their backpack.
Needless to say, it would not be a very pleasant situation to be in.
Sources:
Pictures about "What does a Valve Anti-Cheat (VAC) notification look like?"



Do you get a notification when you get VAC banned?
When you are banned. According to the TF2 Wiki, you will recieve the following notification when you try to connect to a VAC-enabled server.How do I know if my Steam game has anti-cheat?
On the store page on the right hand side(scroll down a bit) you will see information saying "Valve Anti-Cheat enabled" If you go on the Cs go store page you can see it for an example. example Sniper Elite 4. has VAC.What does Valve Anti-Cheat detect?
Valve Anti-Cheat (VAC) is an automated system designed to detect cheats installed on users' computers. If a user connects to a VAC-Secured server from a computer with identifiable cheats installed, the VAC system will ban the user from playing that game on VAC-Secured servers in the future.How do I get rid of Valve Anti-Cheat?
VAC bans are permanent, non-negotiable, and cannot be removed by Steam Support. If a VAC ban is determined to have been issued incorrectly, it will automatically be removed. If you wish to discuss Valve Anti-Cheat with the community, you may do so here. What is VAC?Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Pixabay, Shiny Diamond, Marta Branco, Amina Filkins

