Oh come on! Bitvest is the worst campaign I have been a part of. They are basically paying people to spam forum with load of useless messages. And the payment is so low I can't believe that there are still people willing to be in the campaign.
You can call it as a worst campaign but it's one of the longest paying campaign for a reason. And users who are joining is one the reason why it's still running until now. While calling it as a
scam is just an accusation until you provide a valid proof to back your accusation.
You're aware that scam is different from spam, right?
Do you really need a proof of that? You can easily compare the number of posts the users will write this week, while the campaign is paused.