Chekhov's law of relevance

This post is a response to an Emergency call for the pragmatics police by Mark Liberman on Language Log.

There's a story today in the New York Times about a planned "major expansion of the city's information hot line, 311, ... undertaken just in time to help thousands of visitors to the Republican National Convention next month navigate the city by simply picking up a phone". Terrific, but can somebody tell me why the picture that runs with the story -- at least in the online edition -- shows a sign on the wall in Yiddish?

There must be a journalistic variant of the famous Chekhovian law of relevance for suggestive details in literature, two versions of which are:

"One must not put a loaded rifle on the stage if no one is thinking of firing it." ---Letter to A. S. Lazarev-Gruzinsky, Nov. 1, 1889.
"If you say in the first chapter that there is a rifle hanging on the wall, in the second or third chapter it must absolutely go off. If it's not going to be fired, it shouldn't be hanging there." --- from the Memoirs of Shchukin (1911)

Let me propose a journalistic lemma: one must not put a foreign-language sign on the wall in a picture of an American municipal office, if the story is not going to comment on it. If it's not going to be mentioned, it shouldn't be hanging there.

What interested me about this is that it seems that Chekhov's law might be derivable from the communicative principle of relevance with some extra assumptions. All that communicative or pragmatic considerations as such say about the situation according to relevance theory (Liberman only mentions Grice) is that the details of a story should turn out to be relevant enough to have been worth attending to and processing.
It's not clear to me just what is the extra assumption that Chekhov needs to derive his law. Whatever it is, Chekhov's law presumably only applies to certain styles of writing, as contributors to the thread on Chekhov's law seem to discuss:

Of some note in this regard is the opera "The Abduction of Figaro" by P.D.Q. Bach, in which three separate characters, at various points in the action, wave guns around, but never fire them.

(On the other hand, one of them does toss a hand-grenade...)


Ok, I can't let this thread go by withoug mentioning that Gogol (who died before Chekhov was born) was a great writer because he violated this rule. I can't think off-hand of an example in his plays, but the first few paragraphs of "Dead Souls" is spent describing in detail the appearance of a youn man coming out of a tavern, down to the style of pin and type of embroidery in his clothes. This person is never seen again and has nothing to do with the story at all.

And the modern author, Vladimir Voinovich, in tribute to Gogol and thumbing his nose at Chekhov, made sure he pointed out a shotgun, foreshadowed it heavily, only to have it fail to fire at the critical moment in The Life and Extraordinary Adventures of Private Ivan Chonkin.

On the other hand, all of these might be seen as examples of deilberate flouting of expectations to create comic infelicity, so there's perhaps no example here of literature entirely outside of Chekhov's law. Still, it seems to me that it can't be reasonable for journalists to remove real details that fail to conform with our (stereotypical) expectations: life is richer in details than we expect, perhaps, and I don't think we need to be protected from that.