However, there is no mention of anything in "General Rules" the project can change any rules or anything during the bounty just like other projects did so they can easily ask user KYC or reduce token. So basically, they broke their own bounty since there is no rules project can change.
True. All these altcoin projects are perfectly aware of the fact that bounty hunters can't do much damage to them, so they simply don't care about the aftermath of such decisions. Worst of all, all these bounty hunters that got screwed will join another bounty campaign, that will probably do the same thing to them like these BIRB guys. Rinse and repeat.