Nobody sane would, intentionally. But I'd bet the house on it happening by accident quite a bit. At a technical level, I like this idea. When used well, it mak

Nobody sane would, intentionally. But I'd bet the house on it happening by accident quite a bit. At a technical level, I like this idea. When used well, it makes sense to allow. It's hard to fault it without bringing in human error, politics, or economics. At a practical level... I can't wait to see what happens when a bug allows Facebook to serve this header on all pages, even for a few minutes. The most Facebook dependant folks around, those checking their phones every five minutes, will be stuck in a perpetual time freeze, unable to move forward ;). I also can't wait to see what happens when a government tries to ban a cache-control: immutable page. Or even what happens when, someday, Google is selling it's assets and gets to "google.com.". (Someday, itll happen - Google won't exist for all eternity)