One thing I discovered is that in the past, there used to be signature campaigns that at least Jr. Members could join. It wasn’t just about the earnings. I believe these campaigns encouraged newcomers to read more, research, write better posts, and participate in meaningful discussions.
This is at the discretion of the campaign managers together with the company they are advertising for, if they see needs be, then there is nothing to stop them from making use of jr members, as long as they are going to be selective and not abuse signature promotion by taking in spammers to their campaign.
This could be why some of the newbies are not that considered, some of them are not experienced enough in making up to the standard of the required quality post.
Do not just automatically accept any user that signs up to your campaign. Check their posts first. If they're all short sentences or unsubstantial or in very poor English then they're likely not going to change their habits. If every campaign only accepts and pays for users who have made fairly constructive posts then this will instantly clean up the forum as any poor posters will have to improve if they want to earn anything from a campaign.
And most importantly, this also is part of the reasons why higher account are most considered because a campaign manager could be held responsible for any indecent post made by their participant.
Consider only accepting higher-ranked accounts. Not only do lower-ranked members tend to make the most spam, they also have limited signature space for your advertisement. Full Members and above would be recommended, but if you want to pay Newbies then that's entirely up to you, just remember that you are responsible for the posts they make.
Many of the high-ranking members today probably had their spark from those early opportunities.
Things change over time, you may not expect the way the managers operate years ago to how they do today, moreover, we are not posting quality content because of the opportunity we serve to earn from this forum or signature campaign, instead, because of our passion for bitcoin, if the opportunity comes, then fine.