I have seen a lot of credible bounty managers here where in the end they've became greed and abuse their popularity here in the forum, while doing some activity which is illegal like they run away the fund of the owners of the project they managed then some are doing cheating abuse, or etc. Meaning, credible bounty managers is not enough to say that the bounty is credible.
I think as long as the bounty team of the project is transparent to their community, the the project is running in good progress, and always giving an updates to all socials media they have I could say that campaign bounty is credible.
You would not blame a bounty manager for what could happen to a project and I think a lot of people just like the idea of being spoon fed most of the time.
This is not something that we just have to keep pushing blame, because for every bounty participant that ended up joining a scam project, they are just as guilty as the campaign managers themselves, because they could have averted that easily, if they had taken their time to at least do some pretty good diligence on the project they are participating in its bounty.
Bounty campaign has its own risk too, and you have to live with it. Sometimes, you may even participate in a project's bounty that you believed in but ended up not reaching its soft cap, and then investor's money are refunded, which in this case, shows basically that there will be nothing for the bounty participants. It is all part of the risk.