The most difficult part of having a cheater tag is that on your own screen. The game's anti-cheat system is local to each player; while other players' games will display the red "CHEATER" label above your character's head, your own client will usually hide it from you.

: Using more deployables (like doctor bags or sentry guns) or throwables than your skills and loadout allow.

The most straightforward way to answer "How to know if you have a cheater tag" is to look at your screen. However, the tag behaves differently depending on whether you are the host or a client.

: If you are instantly kicked upon joining public games that have "Auto-kick Cheaters" enabled, you likely have an active tag. Chat Messages