If some of your participants happen to have been in BD management, you may be doing the right thing assuming that most of the members (which I think are trustworthy) in this thread have rated the quality of their work as poor and the results unsatisfactory.

However, it is not justified to beat your score evenly to all participants. There may be some who work seriously and deserve to be paid. Unfortunately, there is no written agreement in your bounty thread that you will only pay qualified hunters. I guess you have known beforehand that most of the bounty hunters really don't understand what they are promoting. They will only do what they are told in writing.