Valve has banned a record 95,000 accounts from Steam games in a single week. It seems likely a specific cheating method was identified before the ban-hammer fell.

The stats come from a third-party database, which tracks details of Steam activity including bannings. The figure for accounts banned via the Valve Anti-Cheat System normally hovers around one or two thousand a day. Last Wednesday it rocketed to 28,467 before peaking at 61,488 the next day.

VAC is designed to catch anyone who modifies game files to gain an advantage over other players, a natural risk for PC based gaming with locally-stored files. Valve says the system “reliably detects cheats using their cheat signatures” and then automatically bans the accounts. It’s not a negotiable punishment and can’t be manually reversed by human staff.

Given that set-up, the most likely explanation is that Valve figured out a widely used cheat and automatically banned everyone who was using it. The bans only apply to a specific game, with the relevant accounts no longer able to connect to VAC-Secured servers. Some games do have non-secured servers that can be used, though by definition cheaters will struggle to find non-cheating players to take advantage of there.

It seems the bans have been particularly costly for some players with a Reddit post highlighting one account banned from Counter-Strike Global Offensive that had collected in-game skins with an estimated real money value of around $30,000.