Why doesn't Siri strike 2 tones when she asked a question

Hey! So this is the thing iOS 6. Ok cool but I defitnetly believe that Siri needs to have more potential. Siriously! I use Siri very frequently and the main problem that I have with Siri is this. Is it too much to have Siri allow you to talk back to siri without you holding the headphone button. I think that everytime Siri comes out with a question mark. You should be able to just wait for the rapid 2 tones and just talk. Siri will be more interactive and more as an assistant. Plus I don't think that it wouldn't be hard to put this in a program. ? 2 rapid tones respond.