Valve has widened the ability for players to be banned on Steam by granting developers the right to direct player bans directly.
Playing games should be fun,” Valve said. In order to ensure the best possible online multiplayer experience, Valve allows developers to implement their own systems that detect and permanently ban any disruptive players, such as those using cheats.
Game developers inform Valve when a disruptive player has been detected in their game, and Valve applies the game ban to the account. The game developer is solely responsible for the decision to apply a game ban. Valve only enforces the game ban as instructed by the game developer.”
This means that players do not have to be caught out via Steam's VAC or Overwatch systems to be blocked from a game and can instead be identified by a means of an individuals developer's choosing.
Developers have always been able to identify cheating players and block access to their own systems – From Software, for instance, regularly bans Dark Souls 2 players from accessing the game's public servers and pools them into a separate banned player server.
But this is the first time that developers have been given control of bans handled by the Steam client. The process for players to dispute bans has not yet been outlined.