Don't you have to say 'OK glass, take a picture'? Seems a lot more obvious than using your phone, unless you can also tap the side of the case to take a pic. I

Don't you have to say 'OK glass, take a picture'? Seems a lot more obvious than using your phone, unless you can also tap the side of the case to take a pic. I could be casually checking my phone, and people on the other end wouldn't know I'm using the camera in a noisy place. How good is noise cancellation on Glass anyway? Would it still work in a busy bar?