Ranked battles back when it was tier 7. Let me set the scene. Map: Northern lights. Myoko. I have 4 kills. 10 minutes left. I turn to port and pre-torp into an enemy smoke screen. Looking away, I focus my fire on an emery Nagato. Literally 10 seconds later: "Don't fire at your allies!" I had torpedoed our friendly Mahan, who had conveniently sailed right in front of my 6 torpedoes. Annoyed by this, I apologize and continue fire on another enemy Myoko. After launching torpedoes at him, I look to my starboard, and see a Colorado on half hp sail into every single one of my torpedoes. He dies, reducing my kill count to 3, and I get banned for team damage. Needless to say it was a pretty sucky day.
Besides, the Colorado sailed into them on purpose. He had announced at the beginning of the game that he was going to get one of us banned. Grr.