Three professional Counter Strike: Global Offensive (CS:GO) players have received permanent bans from the online game for the use of third party cheat software, just days before one of the largest game tournaments is set to occur.

The three professional gamers in question are Gordon “Sf” Giry, Hovik “KQLY” Tovmassian, and Simon “smn” Beck. The cheat used by the players very subtly enhanced their aiming ability, which can be difficult to detect amongst already fast-playing pro gamers.

The players are not only disqualified from future tournaments: they are permanently banned from the game itself.

CS:GO uses Valve Software’s Steam client to connect with game servers. The client uses the Valve Anti-Cheat System, commonly called VAC, to prevent players from using hacks in all of the games that use Steam, including popular titles like Team Fortress 2, Call of Duty: Modern Warfare 2, and Half-Life 2.

According to Steam Support, VAC bans are permanent with no chance for appeals.

Tovmassian issued an apology to fans and teammates on Facebook Inc., and he claimed that he never used the cheat in a professional tournament, but there is no way to be sure.

Titan and Epsilon, the teams to which the banned players belong, have also been disqualified from the upcoming DreamHack tournament.

eSports: Serious Business

For most people, the idea of professional video game players still sounds a little ridiculous, even with the recent rapid growth of the eSports movement thanks to streaming sites like Twitch.tv and uStream.tv. The idea that someone would use third party game hacks to win might seem even crazier.

But the prize money for upcoming DreamHack Winter 2014 video game tournament being held later this week is $250,000 – enough money to make some players consider less legitimate methods of winning.

DreamHack’s head of eSports, Tomas Lyckedal, told a Swedish newspaper he was disappointed in the banned players.

“It’s never fun when things like these happen, but at the same time it’s the reality we have to face,” Lyckedal said. “I don’t think a pro player has been banned like this since 2001. Of course people have been caught cheating but it’s always been semi professionals, never established players. And it’s a shame it has to happen so close before the tournament.”