Comment 9 for bug 278764

@joosteto: What you are seeing is the correct behavior, since the examples are designed to be interactive examples, and when no GUI backend is specified, there's not much matplotlib can do. The warning is not displayed in this case, because scripts that want to output a file usually have both show() and savefig(), and in that case warning on show() would be unnecessary noise. I think the fix that we're all clamoring for -- to have TkAgg be the default backend -- would address your concerns. Is that the case?

@Joerg: You and I are in full agreement. Hopefully the packager will make that change.