Valve Anti-Cheat (VAC) runs on all competitive systems; Tournament-specific anti-cheat clients may be required (e.g., FACEIT Anti-Cheat); Peripheral device checks: mouse and keyboard firmware verified at LAN events
Why people argue about this
People often assume that just because players are tested for prohibited substances, they're automatically banned from tournaments if caught using them. However, the actual process is more nuanced: a positive test triggers an investigation where anti-cheat measures are applied based on severity and tournament policy, not necessarily immediate bans.