To be discussed. The system could show who marked the user as spammer. And there could be an option for others to unmark him if they disagree or if the post quality improved.
How can we prevent system misuse?(keep hiding some signature).
The same way it is (in theory) prevented right now?
Theymos managing DT and thus selecting DT1, DT1 managing and selecting DT2.
Then there could be a formula to decide whether or not to remove the signature rights
Remember we do not have a clear definition of spam.
It's not about the system deciding something is spam or not.
It's about the system deciding whether or not a person gets to wear a signature based on their "spam score" "post reputation" (whatever it might be called).
Eg can you wear a signature if 2 (trusted) people marked you as spammer? No, probably. What if 2 people marked you as spammer and 2 marked your posts as good.
Cases like this.
I do not know if theymos will agree with you because he already make
Serious discussion section
A test section and at best a tiny band-aid. This can't be the full, permanent solution.