I think that anti theft must have a feature that the user can set query time in tracking te device. I notice that when you locate the device, in just few minutes it will send a notification that the device is not traced. How if the theif is surrounded by buildings? or other obstructions?
And one thing more.
I thing it would be awesome if you can send a comand then the phone will record sound or capture pics via camera and send them to the trusted number.
Or make a call that does not noticed by the theif.