Anyone is eligible to join any bounty campaigns if they want to. But I do agree that as days/weeks passed by, the number of participants in bounty campaigns is increasing. Some may have multiple accounts and joining without a proper knowledge with the project they have joined. But well, since the implementation of the merit system, we should not fear that some of those who joined may post irrelevant replies/threads. Due to this, low quality post has lessen and fake accounts are reduced. Though I still hope that the number of participants in any campaign should have a limit.