I do not think that the managers of bounty campaigns are to blame for the fact that the project was a Scam. Perhaps the Manager was given enough time and resources was devoted to the selection of the bounty campaigns. But often managers also participate in the bounty campaign, wear a signature and also become a victim of deception. Bounty participants and managers must be on the same side.
But they must be the most concern for the participants,and being a good manager he must check the project thoroughly from all aspects before accepting so it wont reflect to his credibility being mager,the problem to the managers this days is what they only concern is the payments given to them and about the obligation for the team wasnt they priority