Every once in awhile when my wife opens her trunk using her key fob the car alarm goes off. When it happened this morning, of course I was standing right by the front bumper.....

I thot maybe she'd locked the car and it was telling her that she was trying to break in...but, no...the car was not locked (it was in the garage all night).

Any ideas? Combinations of things we're doing/not doing to cause it to go off like that?