>That said, I would love for Facebook to put this snippet in their footer.
Google has an effective way to retaliate. Consider all those non-expert users who type "facebook" in the search bar to get to Facebook and who do not know the difference between the search bar and the location bar.
Would you rather have a bug that allows logouts, or a bug that prevents them?
That said, I would love for Facebook to put this snippet in their footer.