Problem
The work stoppage by the union of West Coast longshoremen (dock workers who unload shipments from ocean carriers) several years ago resulted in great disruption and monetary losses for the U.S. economy. The work stoppage occurred due to union opposition to the introduction of scanners to record incoming shipments (which are currently recorded by hand), and due to union demands to increase workplace safety.
Using Marshall's rules of derived demand, explain (i) why union organizers would target longshoremen to organize into a union, and (ii) why the longshoremen's union is advocating the policies stated above.