Cedric wrote the book on unit testing (literally! ). He uses PHP at times when he doesn't need the reliability unit testing gives you and can't justify the extra time it takes.
Given that he works at Google, I suspect his "in production" doesn't actually mean big, real sites.
And I don't care if it's a "big, real" site or not, making mods to a live site is (almost) never good practice. Fix it offline, test it, push.