Why? What were the picketers doing to provoke such response? If my history serves me, this was common in the 30's. But that does not answer the question.
Getting back to cars: Certain high end models of Studebakers are considered full "classic" cars of the late 1920's and early 1930's, along with Packard, Cadillac, etc.
During the depression, rich people stopped buying expensive cars because they did not want to flaunt their wealth when so many people were having a hard time.