Funny you mention this. About a month or so ago my wife said that almost
the same thing happened (well, except for the Petula Clark part) when
driving our '95 E320. She had just pulled out of the driveway and heard a
beep like a warning buzzer. I didn't hear it nor had I ever heard of this
occurring before and since there was no check engine light, etc. I wrote it
off to something else in the car like her cell phone.
Now I'm rather curious as to what this might have been (or is it some
harbinger of imminent doom...).