Wasn’t Poland at the time helping the Nazis, when they annexed Czechoslovakia in 1938?
They probably mistook that the Nazis would have left them alone, while they themselves had no issue with invading Czechoslovakia.
https://en.wikipedia.org/wiki/Munich_Agreement
https://en.wikipedia.org/wiki/Occupation_of_Czechoslovakia_(1938–1945)#/media/File:Czechoslovakia_1939.SVG
Maybe the ones with bras are able to allure more people?