Having a whitepaper is not a guarantee that an ICO is genuine. There are lots of copycat whitepapers and not difficult to spot for the learned. It helps to have a focus-based whitepaper with genuine intention behind it to fulfill the tasks of the project before the ICO.

Whitepapers for ICO could be publicly assessed or privately obtained upon request. It is a red-flag to not have whitepaper at all before ICO.