Same here. I want to make a battery powered noise canceling headphone that automatically shuts off if the jack isn't plugged in. Why should a 250 dollar pair of headphones not do this automatically when the battery is required for the experience!?
Because there's a niche market for people like myself that wear noise canceling headphones without music?
Seriously though, if I go in a server room I'm putting noise canceling on. I still need to hear if someone is talking to me, so no music unless I'm doing repetitive work.
Fair enough. I think you are a very small niche though and my proposal would save tens, if not hundreds of thousands of people from wasting expensive batteries. Worth it.