At a point the team start given excuses to abide by what they promised to do or stop communicating with the community then I can sense the project is scam. How do you determine a project is gone bad and won't fulfil it promise? What criteria do you use ? or you wait for years thinking all will be well ?
I doubt the project specification, first because I often read the whitepaper project so if there is a project that the whitepaper is weird it might be a scam. Then there is no detail like just who the developer and how much their investment (incongruity) might be scam. If the project often delays or is not in accordance with the roadmap schedule or other things that are determined, for me it is a scam because there are no good competencies in the project.