I think if your on the list, and switch to another campaign, the only thing you have to do is not claim payment. You should be fine.
Stunna really needs to update all of this, which is one of the reasons I left. In my new campaign I get paid more for a site I love, and the admin is always online and ready to answer questions about the site or campaign.
It's probably a bit too early to say he's always online and answering questions - Updown was also fairly active in the beginning of his campaign, though that changed quickly thereafter. But I have to admit, a 20% raise in pay rate does seem attractive.