It's totally nonsense! - By introducing such a ban you would limit the posting of the top 60 posters of this forum (from the chipmixer campaign) to 0.5 post per week while allowing shitposter from weak campaigns (or none) to post 100+ posts per week...
My thoughts exactly! If anything, knowing that someone is checking my post quality (first guitarplinker, now DarkStar_ made me much more aware of the need to put some effort in my posts.Disable both signatures, avatars, and personal texts, because people can get payments from their avatars or personal texts. Forum will look purely clean without signatures and avatars.
While you're at it, remove usernames too 
That's going to be an interesting forum with totally anonymous users.Make bitcoin paid signature campaigns the only acceptable campaign on the forum
I've suggested that before, "Tokens" created out of thin air have no real cost and can thus be used to pay as many spammers as possible.Payment in Bitcoin ensures there is an actual cost for the campaign, and ideally there should even be a minimum payment per post.
I don't expect any of this to be changed though, as theymos values the freedom to do things, even if that creates some spam.
What we need is much stricter campaign managers, really its their job to manage their posters & ensure spam is limited.
Simply banning the ones that don't do their job (based on the existing signature campaign guidelines would be a good start already.