What is ironic or unexpected about this story or what makes this story funny

One of the reasons that the kidnappers are so confident of their plan to make big money in short time is that they view themselves as sophisticated con men easily capable of outwitting the country bumpkins in the small Alabama town they have targeted. In one of the author’s patent ironic reversals, however, it is the city boys who turn out to be bumpkins and the simple country businessman who outslicks them at their own game.