All the average person really needs to know to follow a poster auction is that the techniques in color lithography that first made mass production possible for the poster as we know it go back no further than 1870. The lie, of course, was apparent in many posters.
Deception is part of the process of any government in distress.
Only a broken arm. The war posters of World War I invariably presented the war as a crusade. So did another poster artist. The messages on posters aimed at women were mostly to buy government bonds through the Liberty Loans. The rarities brought larger bids.