it is annoying !!! happened to me once, I was driving down the highway...everything nice and good...and it just chimed once and i couldnt make out what in the name of god made that chime noise. It drove me NUTS till i got home (20 mins) and i just kept thinking something is wrong.
It is the day after that i realized the **** 4deg thing...its one of the pet peeves I have with this car