If they're going to use one, they should at least turn it on. She's taken that thing off and on so many times, the beeping should be driving everyone crazy, but I haven't heard it go off even once.
That happened to me once after surgery when I didn't know what it was beeping. I kept calling the nurse and waiting 1/2 hour before one would respond. Finally, when I figured out what it was, I just stuck it back on my finger.