Heheh, just came here to post this. Yes this has been happening while my phone is charging. Random TV shows at random times, I did rewind my DVR when it happened once, play again and a name "Cindy" triggered Siri.
Just happened again watching CNN. The word "Syria" triggered it not once but three times. Followed by "I'm not sure what you said..."
No complaints, the words, how they sound are similar, I can see how it can set Siri off. On the plus side it is working - sensitive, but working. I can always turn the feature off but I actually use it.