I myself also do not know exactly how to distinguish between fraudulent projects and not. because most projects that really pay are projects that have a simple concept. not too much about allocations and other things for bounty hunters
Broadly speaking, usually people will see who is behind a project that is running and see the whitepaper and website. but instead they are smarter by outsmarting all of it so as not to be suspected of being a scam project.
if you are not hit by a scam project because looking at it from having a simple concept, it is a fortune that is hard to come by now.
scam project criteria quite a lot at this time, from just disappearing to giving a reward but the price under the ICO is not even worth it anymore, or delay without any explanation