The recent concert was probably not properly promoted. Wells, who is quite knowledgeable about the concert business, was certain that it would sell out unless it was poorly promoted. But the concert did not sell out.
The pattern of reasoning in which one of the following is most similar to that in the argument above is: My neighbor, who is an experienced home renovator, said the damage to the wall would not be noticeable if it were properly repaired. Thus, the repair to the wall probably was not properly done, since one can still notice the damage.