man, are you kidding?
Sorry, it's my fault. Edit now.

Those two statements seem to be contradicting each other--if there's no way to stop these bounty buttholes from cheating because they can create an unlimited number of alt accounts, then there's not much these projects can do to stop the abuse aside from requiring KYC in order to participate, and I seriously doubt that's ever going to happen.
Actually, I think there were some bounties that required KYC before payout and didn't announce that fact beforehand, but those cases were the exception and not the rule. In any case, I agree with you that it's just way too easy to cheat by enrolling multiple alts in the same bounty, because all you need is to be at Newbie rank--and that isn't exactly hard to attain.
KYC may be one way to limit the number of cheaters in a bounty, but there are not many bounties and owners require participant to complete KYC unless their token or coin have a high price.
We all know that these scammers just join blindly on any bounty, not even that many of them do any analysis. After all, many projects are not seriously developed by their owners who just want to make a profit through sale before being scammed and abandoned. So in the end KYC is not needed by those who only expect free promotion from the participant.