Sounds like a good suggestion, I support it on Scam Accusations board but there is no need for such restrictions on the reputation board
I do not see the need for it in the Scam Accusation board either, OP didn't provide any valid reason to back up his "suggestion", if you are active in the Scam Accusation board, you'll realize that OP isn't telling the truth. The problem is that many users accuse different platforms without any proof or when they are blatantly wrong, in that case they are butthurt when you tell them were they are getting it wrong, and they accuse you of supporting the platform.
The Op actually gave his reasons, but to me it is not convincing enough.
For instance, I promote Evo.io casino, if there is any scam accusation against Evo casino, and I weigh in with my opinion, OP will see my opinion being influenced because Evo pays me. Where I find a fault in his submission is;
Even if signature is disabled in scam accusation, it didn't eradicate the fact that I still promote Evo, so I can still be biased even when the signature is not showing since I still promote Evo.
His suggestions will only bring backlash. It will make scam and scammers hide, because when you disable signature in those boards, people will rarely visit them. So, so many accusations will go unattended to.