I wish they would as well. I've had multiple games this week where my jungler says something like, "this mid doesn't deserve a win" and then proceeds to int 14 some times while the second most deaths was 8. ADC is doing well and carrying the team, so this jungler flashes just to smite the red buff away from our ADC. I reported in game and sent a support ticket, but this player was able to play some 15 games before I got a response on my ticket, which means that's 15 more games he could have trolled in.
I mean, it could be something as simple as if 3+ non-premade people report you within a certain time frame, you are prevented from queuing up for an hour. That in itself isn't a huge punishment, but it prevents this player from ruining a few games in the mean time while someone looks at the game he was reported in.