Who is going to manage a campaign for free?
I think someone who's starting to gain experience as a manager to be added for his portfolio. I've seen some of did this before and pretty sure lately they've been hired for a bounty project.
Those who are the people who never managed any campaign yet so they were trying to get into their foot as manager by providing offer as manage first three weeks for free or just completely for the campaign period but as you said who never have any experience yet can't provide their best as manager even though they are very good poster.