I think there are two reasons why bounty promoters or participants did not get their rewards. One is the ICO project did not become a success for various reasons, the second is the ICO project is a SCAM. It happens to me many times and I'm already used to it... of course, I feel disappointed when the project I joined become unsuccessful, but furious when the one I've been promoting is SCAM. But you know, we do not know who these people are, and we don't even know if they're real - we're only relying on their whitepaper or PDF and nothing more. And the real thing here is, we're not forced to join their project or their bounty program.
.