Not this one, please. We don't want people spamming sections they know nothing about to enroll in certain campaigns.
In general, I think it would be best if every campaign manager prices users based on their own judgment without revealing why. Otherwise, you’ll start encouraging members to do things that could eventually have a net negative effect on the campaign and the forum as a whole.
I also think imposing a minimum number of posts per unit of time is a bad idea, the same as requiring users to post a certain number of posts in specific sections. Obviously, I am not a campaign manager, so I don't know what don't know, but as a member, I do not participate in campaigns that tell me to post a certain number of posts every week or in specific topics/sections. I’m fine with posts in certain sections not being counted, but I still want to post there. (I’ve seen one campaign forbid thier members from posting in certain sections before.)