because most of these hunters are not careful when determining a participation, because it could be that the bounty hunters are tempted by the advertisements listed or often advertised even though they do not know the details of it all, so most bounty hunters are often stuck with advertisements and cheated with gifts
most of them speculate if doing more campaign their possibilities to earn money bigger than they selective accepting campaign. as we know in few months ago there are alot scam project , even that looks very good and team developers qualified. but till reward paid , we could not say it is good campaign or not.