At first it's your core responsibilities to secure your participants payment as a bounty manager.
All bounty manager's should put their participants first and not what they received as payment to manage the campaign, whenever I noticed delay in bounty campaign then I term it upon the campaign manager because they were only interested of what the project will pay out to them at that very moments otherwise, what they could have think is to set a standard of securing participants payment before even launching the campaign. I think there are some bounty manager's who is accepting escrow before launching their campaign, this shows that their participants is their most priority than just rushing to accept a campaign and launched before even thinking of paying bounty hunters.

At this point whom do you blame, yourself or the project owners? To me you have yourself to be blame, excepts you made it clear on the campaign thread that bounty is going to be distributed by projects owners that anyone joining is at their own risk. If the project doesn't pay then no one is permitted to hold you responsible.