I don't know a tremendous amount about cell towers, but I was under the impression that they couldn't very accurately pinpoint locations - I was thinking more of a [foxhunting](https://en.wikipedia.org/wiki/Transmitter_hunting)-style location, where you could (hopefully) find a phone's hiding place with relative ease.

A recent article on how to track cell phone: https://news.ycombinator.com/item?id=14803443

I guess they could use a "stingray" type device, which could be used to control, rather than interrupt the cell signal.

Rectal exams.