Player Moderators. This is what Jagex called them in RuneScape. Jagex even eventually offered some of them jobs..
P-Mods would basically be players looking to help the community, a step up from the Mentor system, a bit step at that.
On RuneScape, P-Mods could mute players, taking away all forms of communication to other players. I don't see why this "muting" can't be done here, expecially if its so painfully obvious that this player I'm looking at is a bot spamming other people. Additionally they could ban, and the ban would be investigated by Jagex-Mods, in this case it would be GM's.