I remember the wife of a letter carrier (yes, they were still called “mailmen” at the time) in the 1970s, who worked with me at the job I had while going to college, practically begging everyone not to put zip codes on the addresses, because that way the mail had to be hand-sorted, and that would mean job security for her husband. It was the equivalent of throwing wooden shoes in the machine, from which the word “sabotage” (sabot=wooden show) arises.
Post 11
What you posted does not make a bit of sense. A carrier is on the end of the distribution line and would not need a ZIP code on anything in order to deliver his route.