The agents often don't spend lots of live time watching Caffrey's whereabouts but they can. They can also look at any time period in the past if they want to check where he has been and when.
If I were a therapist, I might want to investigate the usefulness of such a tracking anklet. There are sometimes research projects where people get a message to report what they are doing at the time of the message: Drinking? Fighting? Oversleeping? The study tries to estimate an important number in lives by such sampling.
When I open my therapy office, I will ask some clients to wear such a tracking device. They might be surprised at the amount of time they are exercising or driving or sitting on their couch. In the novel, "The Girl on the Train", a major character drinks too much. She uses her phone to see who she has called, who has called her, at what hour she was talking with them and for how long. She is ruining her life with drinking but she is able to piece together a view of her activities enough that she doesn't confront the wreckage she is building.
I expect various sorts of counseling and education of individuals will be enhanced by appropriate sorts of tracking and record-keeping if they aren't already.
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