I'm disappointed by the fact that this error comes with a response code 200. I was expecting either 69 or 666 or something of the kind! If your gonna be wonky, why not go all out? ;)
While typically I would discourage using that response code unless the error is with the Accepts header. I would make an exception in this case
Edit: Whoever downvoted me needs to get a life. I'm playing along with the joke not trying to correct amarant.