It shouldn't be up to every single individual user to manually filter out the spam, but sadly, that's what it has come to. We have very clear forum rules as well as very clear signature campaign rules, which are widely ignored and unenforced. Here are what they say:
Staff do not want to hand out bans for unconstructive posts but if we feel that you as a user are continually making very poor or unsubstantial posts due to your paid signature the following bans will be issued:
First offence: 7 days
Second offence: 14 days
Third offence: 30 days
Fourth: Permanent ban
If you are running a campaign and it becomes blatantly obvious to Staff that you are doing little to nothing to stop spam on your campaign you will be issued a PM warning by a Global Moderator that you need to make immediate improvements to curb low-quality posts. You will have 7 days to remove low-quality posters and respond to the message detailing what you are going to do to make changes to your campaign to reduce the amount of spam. If improvements are not noticeable within 21 days of that and Staff do not believe you are doing enough to prevent low quality posts your signatures will be blacklisted from the forum by an Admin and you will no longer be permitted to advertise here in such a way.
Spammers are never banned and campaign managers are never sanctioned. If we aren't even going to enforce the very forgiving rules that we have, then you are going to have no luck trying to get this new feature implemented I'm afraid.
Here's another suggestion instead:
Use ignore. On the 1st of each month (or some other time frame which suits your needs), go to "Profile" -> "Ignore user options" and copy your entire ignore list in to a spreadsheet. Then clear your ignore list and start again. Repeat. After 3 or 4 months, any user which has been on every one of your historical ignore lists gets added to a permanent ignore list. From the 1st of each month going forward, instead of wiping your entire ignore list you wipe it and replace it with your permanent ignore list. This means that you aren't condemning any user forever based on a single post which you hit ignore on, but repeated shitposts will eventually get filtered out permanently. Going forward you can give a user "Three strikes" or something similar before adding them to your permanent ignore list.