Hi, Jon - I come from prune picking & packing country in Central California (Yuba City is the center). Prunes are a bit difficult to pack. Like raisins, they have to be picked, then dried on cardboard trays on the ground, then packed before they get wet and moldy. A rain will ruin them. It's hard work in hot weather. So, yes, prune packing is an elusive quest.
People just don't take prunes seriously, and it's a shame.