If you're a screener and can't tell a Brit from an Aussie (which in a song isn't the easiest thing in the world to be sure of) wouldn't it be better then to not be so cocksure about it and use another reason for the return? There are hundreds of other generic reasons one could give that wouldn't have upset her, even simply "the vocal isn't quite up to the standard the brief is looking for".
It's similar to when they critique real horns while assuming they are midi generated. It's like they are unnecessarily trying to prove how acute their ears are but instead end up doing the opposite.