In my case by talking to my teens about choices, consequences, and how to plan for good outcomes. It helped to start having that conversation long before they were teens.

We had an ios family group set up with location sharing enabled, which was great when they were 12 and losing things all the time (using a phone as backpack lojack isn't necessarily cost efficient, but it was a nice accidental outcome). When they got a little older, they figured out how not to share with us. I was peeved, but proud. Privacy respected.