Welcome and goodbye sounds, do I have the behaviors correct?

I'm curious to see if anybody has determined what triggers the "welcome" and "goodbye" sounds. You probably know what I mean but just in case you don't I'm talking about the happy sounding music that plays when you get in the car and the "power down" sound that plays when you turn the car off.

The goodbye sound seems pretty easy since it plays whenever you turn the car off. It also seems like it stops playing if you open the door before it finishes.

The welcome sound I'm not too sure on. It seems like it just plays when you open a door, then close the door, but don't start the car after so many seconds. Like if I get in the car but wait a few seconds to push the start button I hear the welcome sound while the screens turn on, but as soon as the start button is pushed the sound is stopped. The main time that I notice it doing what seems to be odd behavior is if I go out to the car to get something, open the door, get whatever I need out, and then close the door. When I do this I can hear the sound playing from inside the car in the garage as I'm going back in the house. I guess the car doesn't know if I actually am still inside getting ready to start it or not so it plays the sound just based on the door open and then close events.

Thoughts? I haven't had a lot of time to really play around with this but so far this is what I've observed.