...responsibility of the participants as well to check if everything checks out from a project, if not they should be the first whistle blowers for such irregularities...
That's what
paid Campaign Managers are for.
Though I agree that participants can
voluntarily check the contents if it's plagiarized, you cannot hold them liable when things turned out bad if they miss the red flags.
Managers should be checking companies before accepting to work for them, but participants should also do their own due diligence and make sure they are not promoting a shady company.
Some managers may be blinded by money so it's always good if the participants also help look out for the forum and anyone who may visit.