It’s a very simple idea. The requirement is to be at least lvl 40 to shout in world chat. What if we ban them based on the number of people who block them?
This will work if all players actively block gold seller spammers.
One pitfall is that if the number of blocks is too small, future guilds might exploit it by asking friends to block a certain player to get him banned. Therefore the number has to be large enough for that to happen.
Adding an option for blocking could be an alternative. Simply have a pop-up asking “Blocking player due to: Spamming or Rude?”
Likewise, as the report system is coming up, we can do that for botters. One major pitfall is the same, that is some players just do not like talking. So the wrong ban might be even higher.
On a side note, I think for the system to work, the punishment has to be “Banning” and not simply disconnect the player. Measures such as running captcha does not take into consideration of afk players. Therefore it is unreasonable to ban them just because they are afk. The only option is to disconnect them. However this punishment is too minor to deter botting.
(Sorry if this simply idea has already been mentioned :X)