You must not be familiar with open code (nothing to do with open source or programming) messages where innocent sounding public words or gestures mean something else to those that know the code.
[link|http://www.toratoratora.com/Articles/to----ra/what%27s.htm|Tora, tora, tora.] = "attacking with complete surprise".
You must also not have seen the photograph of American POWs taken by the North Vietnamese where one smiling American is "giving the finger". Apparently a meaningless gesture to the photographer.