Riot, have you considered letting spectators report players?

No matter how hard anyone tries to be unbiased in a match, there are just certain situations where emotion is going to get the better of somebody and push them to report somebody. There are circumstances where a player is more likely to report an enemy and also some circumstances where they are more likely to report an ally.

For example, a 4-man premade is more likely to report their solo ally who did not agree with their premeditated plan or is performing poorly instead of reporting the enemy for being toxic to the team.

And another example, a player is more likely to report a 22/0 Yasuo for saying something rude at the end, but otherwise having been quiet the rest of the game, simply because they were frustrated.

If you let spectators report people, they are not mixed up in the emotions of a match and would theoretically be able to report people more accurately and more fairly.