You can't pause most NPR streams, you can only stop the app. The stream keeps going, and you'll pick it up where it is when you listen to it again. Just like a real radio. There may be some apps that play prerecorded streams, but that's on a station by station basis. (It's not the earbuds that are activating anything, it's that the app you were last playing isn't closed - Android doesn't work that way. Even the Back button doesn't necessarily close an app. (You can get an app like
SystemPanel that will allow you to actually close an app - but Android may open it again.)