It's happened far too many times for me to recount, or even try and dig out links to them, but it usually goes a little something like this: someone finds a rating on the ESRB's website for a game nobody has heard of, and suddenly, its cover is blown. Developers are sad. PR types are making frowny faces. We're left with an announcement, but no details or screens. It's a common occurence, and also one about to be scrubbed out, as - at the behest of publishers - the ESRB are introducing a new means of submitting a game for rating, whereby publishers can request to have a title's entry in their database kept hidden until a specified date (obviously until the PR team announces it themselves). Score one for the marketing guys!
ESRB Reins In Premature Game Leaks [Next-Gen]