You'd expect a person who gave a reason would get more help. Consider the various styles of panhandlers you've encountered. But this obvious conclusion wasn't what Langer was after. But this bogus request matches the pattern of a legitimate request. And the response from the target is automatic.
Heuristics are shortcuts for thinking.
They are ways we can get out of a lot of thought, by employing only a very little. Influence practitioners are skilled at preying upon people who use heuristics. Robert Cialdini illustrates the nature of mindless, automatic responses with a description of the shrewd tactics of the saber-toothed blenny, a small fish that preys on aquatic predators much larger than itself. There is, for instance, a little fish, the saber-toothed blenny, that takes advantage of an unusual program of cooperation worked out by members of two other species of fish. The smaller fish serves as a cleaner to the larger one, which allows the cleaner to approach it and even enter its mouth to pick off fungus and other parasites that have attached themselves to the big fish's teeth or gills.