And remember the RoChu artwork on Chinese news?
How about the massive number of people who use Hetalia fanart for their Facebook status updates?
The Unit 731 article with some... gory Hetalia fanart? (I'll only post this if people ask for it, it's pretty NSFW.)
Look, there're even compilations of things like this: http://nanacka.tumblr.com/post/
Let's face it, we're all just political/historical illustrators for the news now. XD
What instances of "They didn't know it was Hetalia" have you seen? Share them here!