I think it might tell the passenger airbags to work in an accident ? Though I have been wrong before when I guess at things I don't technically 'know'... To the OP, can't help I'm afraid
Mine's very sensitive too. It'll go off if I put a bottle of water on the seat and it rolls around a bit. I've settled on putting bags in the boot and bottles in the cup holders.
If I could get away without one I would but its gotta be plugged in otherwise the airbag light comes on and the bag won't deploy for the passenger in event of a crash!