What choices were workers making at the time?  The choice was made by   
the employers to keep the day as long as possible.  Scarcity existed to   
the extent that workers needed some time to rest and recuperate.  You   
can chalk it up to history if you want, but imagine you were transported   
back in time to give an economic explanation about how people were   
making choices.  Workers had to accept the deal or starve.  Ok, that is   
scarcity in action, but this situation is hardly covered by Robbins'   
approach.  
  
Michael Perelman