What's in a question mark?

Question marks are tricky things to get right, especially in the titles of books and articles. Sidney and Beatrice Webb's reputation never quite recovered from the omission of the interrogation point from the second and subsequent  editions of their book Soviet Communism: a new civilization? Clearly on ascertaining that the rice pudding was acceptable Beatrice had no more doubts. The authors of A New Model of Social Class: Findings from the BBC's Great British Class Survey Experiment seem to be having similar problems. In a strange move  the  new "version of record" has appeared on the journal's website. It is now called: A New Model of Social Class? Findings from the BBC's Great British Class Survey Experiment. One wonders what this new mood of self-doubt signifies? Are we to question whether the model is new? Or are we to question whether it is a model? Or, surely not, are we now being invited to doubt that it says anything about social class? Post-modern irony or proof-reading blunder? Ich weiss nicht, was soll es bedeuten...look out for the rocks!