As a beginner I made this mistake before, but now I am used to studying the project carefully before joining its signature bounty, and if I join I follow the rules strictly (if it is not allowed to remove the signature till the end of the campaign I don't remove it), and I think that's better than joining many campaigns without getting paid from anyone of them.
In my opinion, the bounty campaigns don't have the same weight, signature campaigns are more popular than twitter, facebook or other social media campaigns. The bounty hunters look for the best campaigns in the market and they don't hesitate to apply even if there is no slot in the campaigns. More powerful bounty campaigns don't last more than a few months, these bounty campaigns get filled as soon as possible by the knowledgeable bounty hunters.
Through the IEOs, teams don't plan to use wider bounty campaigns and this foresight lead to the fewer bounty rewards from my life practice. Bounty allocation has been cut by numerous times in the campaigns which take more than a year because the more they look for from the promotion viewpoint, they lose more investors in this time block.