Without team members, an ICO project cannot exist. You probably mean that the ICO team does not want for any reason to indicate its data in the project documents. I have not seen such ICO projects, but I read that sometimes this happens. I would not risk joining such a project. Most likely, this is a fraud. The ICO team must understand that investors and bounty hunters fear multiple frauds in the ICO and should, on the contrary, be the most open and prove that they are not fraudsters. If they do not, then they should not be trusted.