Yeah, i didnt notice on what my rank is so i joined every bounties that i could find and it made me waste my time so much
It's only for signature bounties. You can join other bounties like social bounties without affecting your rank.
No, not all bounty campaign does not require a specific rank in the forum, some bounty requires member rank and up to be able to join social media campaign. It actually depends on the bounty manager of the campaign.