Not stupid at all. After I discovered this I remembered this could be happening and went back and checked. I used a fingernail press to activate Siri. But then I even used "Hey Siri" just to make sure. So in theory you could make a phone call or send a message to anyone you want, from a friend's or even a stranger's phone - without even touching it! The possibilities are endless. Imagine standing in line behind a lady with an iphone in her purse. Or someone's phone sitting at the bar or on a table in a restaurant. "Hey Siri", "message husband". "Tell him he's an a*shole and I want a divorce".