Icos look for bounty hunters to promote their project through the power of social media.Sometimes, some of these hunters also double as ico investors. But it looks like bounty hunters understand ICOs project and are able to determine very good projects before they invest because of their experiences in different projects.
I think these are just statistics. If the hunter gets a permanent reward, he knows that such a type of project often collects a cap. Then it allows you to invest. Well, there is no 100% guarantee that this particular project will work.