The key thing is good posters are able to handle their greediness to hunt for maximum money with max post number. There are some campaigns that have max weekly posts at 50 or 60, and I saw there are many participants don't fullfill max posts.
They usually have a higher pay rate per post, especially if you compare it with Yobit rate. So, missing five posts or so won't give them that much difference. Which is why, a campaign like Yobit tends to increase the spamming from users because they need to get 140 posts a week to get the full payment (around 0.01 BTC or so, isn't it?).
Not saying that Yobit participants == spammers, just to highlight that a good manager is really needed to prevent them from going out of the line.