They are more or less mafias. Either you are in or you are an enemy. Enemies get chained backwards and kept out of top 20. I'm sure every shard chat works a bit different, but that is the basic structure.
My issue is more with the I don't care about wasting crystals people. You get that one guy who will short hop for a revenge hit and then spend a refresh to just go back and forth five times. That is also the problem with the general "hit enemies before friends" rules. You are compelled to go back and forth with this idiots are spend more crystals on a quick refresh to double jump.