1. SC's aka signature campaigns make you feel greedy but if you just want to earn some money by doing something you always do, you can't turn into a spammer. Spammers spam even forums where they don't earn to post.
2. Merit is a personal choice of members and is not restricted to just high rank members. If any member finds your post worthy, they will merit it irrespective of the sig you carry. Not all members ignore users of a sig campaign.
3. If you are a spammer, you would be blacklisted even if you aren't a part of any campaign.
4. Scammers have no reputation while people don't give so much importance to spammers. If you are honest and don't promote a scam campaign, nothing can harm your reputation.
5. That's again dependent on if you spam and has nothing to do with any particular campaign.
6. This point doesn't even make sense