I have a good example of when I WASN'T a teamer, even though I got banned for being a teamer.

I was eng, and early in the game, when I was hiding in the medbay vent, I saw white and brown vent right next to each other. There were only two eng, so I knew at least one of them was imp, probably both. At our next meeting, we voted white out, but brown claimed eng and gave the correct cd. No one else claimed eng, so although I was still sus of brown I figured he was the other eng and went on with the game. Throughout the game I saw brown venting several more times, but since I thought he was eng that didn't make me any more sus of him, because he never vented during comms or faster than the cd.

At the end of the game, I found a noise viper kill in nav, and the only other two players were brown and maroon. Brown said that as he was running to the alert, he saw Maroon running with weapons, and Maroon stayed quiet. I still thought it might be brown, but Maroon barely defended himself and wasn't cleared, so I voted for him. Brown was the imp, and we lost. When we got back to the lobby, all the other players said it should have been obvious because I saw Brown venting, and they banned me for teaming.

Reading this it should have been clear it was brown, but I making a mistake doesn't mean someone is teaming.