They will probably start doing it with accounts >= Member that either have positive or negative trust. If they don't have them, they will start buying them in chunks from people as it does not cost a lot to buy a negative trusted account because people don't use them after they get tagged and everyone would rush in to sell them if they see an opportunity.
So maybe, in addition to that, any post from an account with any rank should not bump a thread to the top if it is red tagged. That might make it a little more workable.
 

Not sure how getting rid of the Announcement board would turn out, but I really like the idea of ICOs paying a certain fee for their listings and running bounties in the forum. I have always wondered why there hasn't been anything like that up until now.