The thing is that very few (any?) phones in my experience have ever played the ringtone out of the speakers when headphones are connected, but that is now - bizarrely - what the N900 does and I'm sure it caters to a few corner cases - your corner case - but the reality is that most people will have the headphones in their ears when the call comes in. You quickly learned that when you were no longer listening on the headphones you disconnected the headphones from the socket...