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Most BTC paid campaign requires you to post at around 25 up to 50 or 60 posts a week. So you'll need to make around 5-10 post a day. Just because you need to make 'a lot of posts' in a day doesn't mean your post will be spammy.
To be frank, ain't know until now what is the real spammy for me, all I know spam content posts are those 1 liner posts(or garbage post). If users posted even more 10 posts a day but it has a helpful and useful content with accurate post gap at least 30 minutes(not 5 minutes gap) probably that does not look like spam.
Since we're generalizing it's safe to say the general answer would be yes as they do pose as threats in some way to the community in regards to scam or spam. Apart from selective few like Chipmixer (that only employs the service of quality/reputed members through the help of a reputed manager), others are either associated with scam or spam.
Maybe that is right upon on selecting good posters and through managing reputed managers because they know what is right and they are all having a concern of the forum, not just because the company gives high rewards to the participants.