No, that is bullshit. If you don't trust them or if they can't be trusted don't give them a phone. Nanny parenting, or pretending you're the NSA is unhealthy for their development, and gives you an illusion of control of their life that is inaccurate and misleading.

Talk to your fucking kid about your worries or their behavior and/or parent them, actually drive behavioral change, but don't bitch out and not parent and pretend the E-leash is helping them or you.

You can do this, but I'll warn you that my mother did this and it destroyed all trust in our relationship. Seriously, not for a week, or a month, it has been 20 years and the trust is still ruined. I didn't even drink or smoke or anything, I'm still angry at her for snooping on me, not trusting me.

She has never apologized or felt any remorse for tracking me. All she had to do was ask where I was and I would have told her. You do this, understand how your child will react.