How does the saying "no good deed goes unpunished" relate to section eight of the book thief?

In the middle of December, a third, smaller collection of Jews is marched down the street. Rudy shows Liesel a bag containing six pieces of bread. They place the bread on the street in advance of the Jews and hide; Liesel hears Rudy's stomach growl. When the procession arrives, Jews snatch up the bread. A soldier notices Liesel and Rudy, and the two run. Liesel is kicked in the backside by a soldier, but the two receive no other punishment. Max is not among this group either.