As I see it, there's no problem for bounty hunters in joining low allocation campaign. I even admire them for having a lot of time to do so. But I'm not saying that bounty hunters should not know their worth. Of course, they know it more than you. If they are comfortable doing it, then by all means they are free to do it.

Also, let me point it out for you, not all bounty hunters are just bounty hunters. Some of them really supports the company they are promoting regardless of the bounty. They believe so much on that certain project that they dont mind the low bounty.