I often come across people, who hearing me speak with the girls, ask "So you are raising the girls to be bilingual?" (implying English and whatever language I happened to be speaking at the time). I invariably smile, and either reply "Hum, Hum, yes ..." or more often "Well, actually, it is a bit more complicated than that...".
I sometimes explain that I speak Arabic and French to the girls, the Babel Father speaks German to them, and the two of us speak French between us. It can be confusing for people. I will be confused if a mum comes up to me and says she speaks Portuguese to her Child, the father speaks German, the parents speak French between them, and they all live in a Dutch-speaking environment (incidentally, this is a real example of a family we know).
It can be reassuring to put people in boxes, know what to expect, and how to generally behave with them. On the other hand, putting our daughters in boxes is not a straightforward. I love it!