However the assumption relies also that this 'evidence' being the reports isn't manufactured as well. I have spoken to people and friends who play the game that will set up others on their team or enemies to spam, to look like horrible teammates. I was in a game once where an individual was amongst every team fight but after the fight the allies would spam about them being in the jungle and not team playing. I was confused as to why until after the game when in post chat they stated if I didn't report this individual with them they'd report me.
It isn't that there's no evidence, it's that it is selected evidence.
As for what to do with reporting, there are two solutions in my post. Consequences for spammed, nonconfirmed reporting (as in punish those who report everyone for everything because it's how they cope with their rage) and also offer a postive report system, a kudos system, to signify players who are a benefit to the community.
As an aside: I'm not, haven't been, nor intend to be, banned. I'm just a player who uses the tribunal system but approaches it from the mentality of innocent until proven guilty, and often I see the guilt astoundingly clear which made me question why I only get to see the moments of crime without a lot of context.