Curangel has a functionality where it tells people who were chosen for curation but participated in certain activities in the near past that this has disqualified them from curation. But that only reaches a few, and experience shows that only a small part of their users cares.
The problem has to be solved at the root, by hurting the service providers. Or warning them, as this worked decently here. There are quite a lot, I won't write a post for each, instead I hope the whole community realizes that it's important to highlight abusers and root them out before they become big and many get hurt.
I'm glad you made this post, this is kind of what I was referring to earlier, when I was talking to Acid. Shifting culture. Step 1 is awareness. I for one, had no clue this was happening.
I don't disagree per se, but, maybe a transparency bot would help too. Listen, I'm not married to the idea. I'm going to think it over for a while.