I guess Yobit should have gone through the "needs approval" route instead of paying people until they get banned. It shouldn't be a major issue tho.
Yeah, that would also decrease the workload for yahoo. I think they should add a script where users need to get approved by yahoo before they can start earning satoshis. Should not be a huge problem to do that. Or, they could go the traditional way with a spreadsheet and stuff like that. Easier to track participants and increase transparency. More importantly, the funds should be escrowed. Their last campaign didn't end well and IIRC some of the participants didn't get paid.