So I'm willing to take responsibility for putting the cat among the pigeons, but not for taking the pigeons by surprise. The situation was that a lot of users were ready for this experiment and it was simply a matter of someone doing it.
"Hey, let's practise our French" might have been a title, but that wasn't really what it was about, and we couldn't go on using that kind of title for all non-English diaries. One thing I did think of doing was including a summary of the diary in English, and perhaps I should have put in the extra ten minutes. In fact, if we do more other-language diaries, maybe that should be a rule. It would allow non-speakers of that language to get an idea of the topic. They could then, if interested, use a translator to find out more. If still uncertain of some points, post an English comment to ask for guidance. The point being to include, not to exclude.