I want to use the find my iphone app to track my daughter's whereabouts. I have enabled restrictions and put pin only I know on it. It locked to start with, but following a restart she is now able to turn off the cellular at will. Is it possible to permanently lock the data setting to ON?
I highly recommend Life 360 for your family circle. There's tracking, tracking history, a check-in feature, a panic button feature, feature you can set up to alert you when they arrive at an address and leave an address (school for example), in the map for Life 360 you can see where the convicted child predators are, you can see where all of the hospitals, fire departments, and police departments are. If your daughter is allowed to keep her phone on in school, then you'll know if she turned it off. You can see it in Life 360 because the battery icon for her phone will be gone. Life 360 also has a location request feature. This app does so many things, there's no way I could write it all down in this post. It's free.
When my kids where younger I gave them a choice; either use the phone responsibly, check in diligently with Life 360, on time, and frequently, and never disable the GPS (they had to turn phones off in school, and this was the only exception). If they broke those rules then they lost their phones for 2 weeks. No if ands or buts. With Life 360 it's a two way street. I did, and still do, check-ins to let my loved ones know that I am ok if I am not home.... I have family members in my Life 360 circle in 2 other states.
You can't really lock the data settings. It's up to you as a parent to enforce your rules.