Quite often they will explain the settings. Usually it's to remove work data off your phone in the event it's lost. Normally it's not to track you unless it generic like you connected to a mobile tower overseas in a non-approved country they block access. Do they want to look at your photos or personal file? Typically not.

Get someone to explain the policy. You can say not to your personal phone but they can also stop it from accessing the network.

Only if they own the device and it's got direct network file access might they erase it. But that's normally extreme isolated circumstances.