Seems OP probably have a problem with signature campaigns as the neutral feedback left by @bitbollo says it all. OP why not rank up your account and participate in a signature campaign so that you will reduce your hatred for signature campaigns.
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.
Inasmuch as i do not agree with the idea of OP but saying that there will be less engagements in those boards if signature codes are not displayed is not true, there are still sections and threads in the forum that generates enough traffics even though advertising codes are not shown. Perhaps, the reputation and scam accusation sections are very sensitive so i doubt if users will lose interests navigating in those sections just because signature codes won't be displayed.