These were great links to the SEC warnings about how the quoted share price of a company may be hyped including by touting an ICO.
What the SEC did not cover is the risk relating to contributing to an ICO itself. I think the reason for not covering ICOs themselves is that the SEC is sitting on the fence. They don't want imply that some ICOs are legit, nor do they want to cut off the range of financing available to a genuine company doing a genuine ICO.
They want to put rules in place first.
As for the promoters of fraudulent schemes and HYIPs, they are at the greatest risk of prosecution if they were receiving compensation either from investors or from the company itself. This would include all referral programs.
For my personal conscience, I would not want to accept money (referral program), for touting an investment where investors lose money. It's like pushing crack cocaine on new users, so that I can make the addicts into my customers.