It has nothing to do with being known or not. You claim it was accidental due to no banner, but it tells you in the chat box if you hit an enemy. You do not think seeing that would give you a clue even if "his banner was not showing" after 5 hits? Yes, you do have a ban record in fact in the past for team killing, which is why I gave you the length of a ban I did.
I was getting reports of you in admin chat that night of team wounding, but every time i went to spectate you I never saw it. Unban request denied, I hope this break will teach you to play nice and stop team killing.