Banning people for "combat logging" is absolutely ridiculous and should never ever EVER (did I mention ever?) be a thing. It would basically be like holding up a giant "GTFO" sign to everybody with crappy internet, because there's really nothing anybody could do about that, except eventually get permanently banned for lagging out/crashing/etc. That would be like banning somebody for using a different mouse than somebody else. Seriously, this "problem" could be solved by just fixing item drops when disconnecting.
Now, taking into account the edited information: Why would you be complaining and want someone punished if they literally gave up and let you kill them? Sure, stuff doesn't drop now, but that's a bug and its going to be fixed. There doesn't need to be some silly system created to ban players who leave the game, it would be much simpler and faster to just fix the bug, which I'm sure the developers at least know about, if not already working on fixing it.