The practical approach is to make things hard enough to discourage theft in the first place or make life harder for the thief afterwards. You cannot usually cover all possible scenarios for a trained insistent attacker.

The same way having a secure password protects you from Brute force attacks - https://xkcd.com/538/

Is this standard iPhone thief operating procedure?

Pickpockets usually don't carry freezers or lead boxes on their person. By the time they are home and can drain the phone, their closest WiFi access points would have pinpointed them.

(Though a sophisticated thief might have a lightweight faraday cage on them - sleeve lined with aluminium foil might sufficiently dampen Wifi/GPS/cell signals.)