I have a few bounties that have not been paid, it's unpleasant, but at times nothing can be done about it. It is necessary to give the analyst more time.
Many projects overestimate their capabilities, so the ICO does not collect enough money. As a result, they return money to the initial investors and can not pay for the work of bounty hunters. If this is not a fraudulent ICO, then we can only regret the lost time and come to terms with it. If we were deceived by fraudsters, we should unite and decide how we can punish them.
Participating in a bounty means we have to accept risks when the project is deceptive or unsuccessful. We can waste our effort, but we do not lose money, the rewards may or may not be available.