Ankle/GPS monitors have potential other uses.

[Chromatix]

Losing the signal indoors would be okay. It's when they wander outside that the signal is needed, and it's much easier to receive the signal from the satellites there.

I assume that the return signal would be via the cell network, which offers a backup solution through triangulation, not as precise but still useful. It would be enough to confirm that the subject is inside a particular large building or in the vicinity of a particular field or river.

One particular difficulty of tracking sex offenders is that they might actually try quite hard to disable the tracker, and this might account for at least some of the reliability problems. This is somewhat less likely with a confused senior.

[PepperElf]

Does their using the same technology necessarily mean they're involving the police?

The ankle-device program suggested came from a police officer and specified police monitoring. It's in the article.

[HYHYBT]

I realize that, but that it was specified in the suggestion doesn't mean it would be implemented that way.

The reason I brought up GPS's losing their signal indoors is that you don't know where one is between when it's lost and when it's found again. But as mentioned, someone at themselves enough to figure out how to shield the thing isn't going to need one for this usage anyway.