I think this is separate from the core argument, I don't think anyone would make such a device. However, but a building with metal siding and few windows might be sufficient. Except for the fact that I installed a repeater, some parts of my shop would completely drop detectable signal, other parts too weak to let useful signal through. Some stores are like that too, I can get in the middle of the building and get no signal. This counts a Target, Walmart and a local grocery store. Anyone working in a warehouse might be in trouble.
I don't think any medical device will require a constant signal to keep the patient alive, there's too much risk in that, I don't know exactly what circumstances would require that. I can see maybe a medical device for a seriously ill person that relays location and vital data to dispatch an ambulance, one might be in trouble if you lose signal and you have a life threatening episode.