I was playing a game with Zed and Jax in my team. Jax started losing against Riven and then started trolling. He was wasting spells, putting a few wards in base and then randomly flashing.
When i said "can you stop trolling", he replied with "like someone cares, reported noob".
Not many minutes after, Zed was making malicious plays and clearly had no idea of what he was doing. He was going versus 3-4 people every time and just "having fun" and "joking" the enemy team with 43 farm late game.
I also have a replay video if that will help, but all i wanted to do here is raise awareness about this issue. I also think that players like Zed need to be banned.