I subscribe to the theory that, because of the mesons and neurons that Al and Sam
and Ziggy share, coupled with Ziggy's highly advanced technology, she's able to track certain of Sam's physiological responses
i.e. heart rate, blood pressure) and does so during a leap. So, knowing the range of Sam's baseline normal readings, if he gets into a situation that would cause his blood pressure or heart rate to rise abnormally sharply, and if Al's not with him, Ziggy would notify Al immediately. So, as I see it, Ziggy is the "constant monitoring/early warning device" that enables Al to always have instant notification if Sam's in danger.
Like I said, that's the theory to which I subscribe.
Eleiece