People behave the way they behave, not the way our logical analyses and wishes would have them behave.
People follow their interests, their needs, their customs.
They are driven by curiosity, boredom, emotion. What Benway and Lane found was this. Nobody could possibly miss it. Lo and behold, Benway and Lane showed, it was the rare individual who noticed that this bold and salient banner contained the information being sought. People are lawful.