This is the risk of joining any bounty, that is why before joining I will not expect a lot first because it hurts a lot when you get nothing in the end. Last year out of 20 bounties that I have joined only 2 gave rewards and some of them just dissapeared or abolished their project.
Yes, now bounty hunters are simply defenseless in legal terms. This activity is in urgent need of streamlining and regulation. It is necessary to establish an elementary order with a clear establishment of the rights and obligations of the parties. I think it will be soon. States are already very close in regulating ICOs, since very large funds are involved in it, and thefts and frauds reach astronomical amounts.