I'm guessing you mean that the project doesn't have a whitepaper and they have a bounty campaign going? As a investor, I wouldn't say it's 100% a scam project because of this, but I would be very curious and would be watching its development before investing into it.
There are too many investors and Dev team can not support everyone if they want to ask about the project. That's why we need a whitepaper. Investors can ask when they have questions about wp.