In my opinion, ICO who does not publish whitepaper then the ICO can not be trusted. Meaning that ICO is not serious in making this project a success. ICO without whitepaper is a fraud. Whitepaper is a good medium in bridging between companies and investors. Without a whitepaper then investors can not understand and know the ICO clearly and deeply. Of course, if I am an investor then I do not want to invest in the ICO. My advice, you should not join ICO without the whitepaper. You will only put your money at a loss if you join the ICO.