It's been a while, but I think Julie Andrews took a double-take on that line too.
Douglas Adams took note of this one, too, and organized a contest to figure out a good replacement line -- it's documented in 'Salmon of Doubt'.
Best I managed to come up with: "La, a set of formal rules!"
. . . which doesn't really mesh with the tone of the rest.
Good call, I was just coming here to post that. In fact I found a web-site that has that particular gripe of Adams on it.
It's bugged me for the longest time too.