Everything sometimes goes into 'speaker' mode for some reason. I've found this happens on a friends iphone 4s as well. It seems both 'Ringer' and 'Music' volume controls both affect certain things including ringer, lock sounds, and alerts. To give an example turn ringer all the way up. Go into the 'music' app and turn it down. Hit the lock button, and then unlock the iphone. You should hear the lock sound activate but no more unlock sound. Now turn the music volume all the way up and lock and unlock the phone. You'll now hear the lock sound stay normal, however unlock will be super loud. Can anyone else confirm this?