NicholasW wrote: The example quoted in Chambers is that No smoking abaft the funnel implies that smoking is allowed before the funnel.

Hyla responded: This seems to get us back to the first post in this thread - wouldn't assuming that one could smoke before the funnel be begging the question?

Certainly in the world of symbolic logic Hyla would be correct but in the real world (if there is such a place) the notion of forbidding some specific action in some specific place would be taken to imply that that action was permitted in other places.