Some bitty in Milwaukee (warning, Fox News, remove your brain) got her knickers in a twist over graffiti in her neighborhood that read "Where da bitches at?"
Now, I like correct grammar as much as the next English teacher-- unless it's an English teacher in Taiwan, but nevermind--however, I think that, since this has been a recurring nightmare for the last several decades, it's time for the new generation of grammarians to ease off and allow popular usage to help the language evolve. If it wasn't for language evolution, we'd all be talking like Chaucer.
So, if you're out there writing, throw some prepositions UP!