What if a hostel student has a second phone that Skie does not manage?
Skie controls only the device it manages. A second, unmanaged phone is outside its reach, so the hostel agreement should cover personal devices as well. What Skie can do is make the managed device the useful one, and flag when a managed device goes silent or leaves the hostel.
This is the question every warden eventually asks, and the honest answer is that no device management tool controls a phone it does not manage. Skie is installed as the owner of a device that has been set up through it. A different phone in a different pocket is simply not part of the system.
So the policy has to carry some of the weight. The hostel agreement should say that personal phones are covered by the same rules, that the school may ask to see devices on suspicion, and what the consequence is. Parents sign it too. Physical measures still have a place, such as a locker or a collection routine at lights-out.
What Skie adds is a managed device that is more useful than the alternative. If the managed phone has the apps students need and can call home, there is less reason to carry a second one. Some hostels issue a managed device and require the family's own phone to stay at home.
Skie can also show the warning signs. A managed device that goes silent or sits offline for long hours at night is flagged in the breach centre and the last seen time. A device that leaves the geofence raises an alert. These are indicators and not proof, so follow up with a conversation.
No tool changes the fact that a determined student can hide a phone. Better to say so to parents than to promise otherwise.
A practical tip: ask why the second phone exists. Students often hold one because the rules on the first are felt to be unfair or too tight. A small adjustment to a window may remove the reason.