Comment 6 for bug 711345

Indeed it would not Lars. Apps register with the sound menu by the sound service monitoring DBus. Any app that brings up the DBus name in the form of org.mpris.$APP_NAME will grab the attention of the service and if compliant will appear in the menu. At this point the app is remembered via GSettings and from that moment on will appear in the menu even if the app is not running.
To remove the app the user needs to remove it from the i-sounds GSettings ...