Aunt Marge scene & Petunia (foreshadowing?)

[kjirstem]

Watching POA again recently, I thought that Petunia's reaction to Aunt
Marge blowing up was surprisingly calm in the movie.  For the most
part she just watches and moves out of the way to stand over near
Harry.  She doesn't look quite as foolish as Vernon. Looks rather like
she's somewhat more used to dealing with magical happenings than might
be expected. 

Which makes me wonder if the extent of Petunia's familiarity with the
wizarding world is one of the places where there is foreshadowing in
the movie.  Of course, OOtP makes it clear that Petunia knows more
than she lets on about the WW but we still don't know just what and
how much she does know.  

Anyway, wondered what others thought about this...
kjirstem