Do trolls who mess up their allies get punished?
I was against a Tahm Kench who was "jungle" but instead of going into his jungle he just went top lane so I was 1v2. Instead of trying to help his top laner beat me, he just stole CS, including smiting every cannon minion he could, and then my jungler came to gank so he devoured his ally and walked into us to give us the kill. Then he ran away.
Of course he wasn't toxic in chat and he didn't die a lot, so it seems like the system might not detect anything wrong with how he played. We reported him but I'm doubtful it mattered.