@FibS that's why I also suggested their posts not be visible until approved by moderators (full chat ban wouldn't even need to exist at all).
So instantly after an account is made, they get to post (spam) but no other user (besides mod) sees such spam cus their posts are invisible to other players by default. Moderator comes and if post is ok, he makes it visible to other players, and if he sees spam bot, he bans the account without his post ever becoming visible to normal players.
Once account matures and moderator sees he made enough posts like a normal human and over appropriate amount of time, he can mark account as verified, and he can now post with his posts instantly becoming visible without moderator action.
This would make things much harder for spam bots, because each account would require a whole week of normal active human usage before it could be turned into bot account (practically no one from spammers would bother with that).
Big minus is that this would require a lot more moderator work, so that's why we all hope this new measures that were installed recently will work nicely. So far they do. 