> Why not decide that the sensible non-interactive behavior is to behave
> as if the answer is NO?  Can you think up a use cases where this would
> be terribly wrong?

If you have a complex setup, particularly involving frames (which are also saved). 

> FWIW, IME, whenever I see this question (interactively, of course),
> the correct answer is always NO.

In my case, the right answer is almost always YES (i.e,, I almost always want to save the desktop).