My wife's Altima (with a fob) has done that for years. It is simply baffling at times. We just make sure the lights aren't left on, and that one of us hasn't left the other fob inside the car.
She is usually more OCD than I am about such things, but she has simply chosen to ignore that. But in the land of OCD:
Limeybastard >>>>>>>>my wife >> me
