They should have carried a Spot locator.  Then the student would not have had to hike within cell phone range.  It will send a message with your location to the nearest Search and Rescue operation by Satellite.  My wife and I carry one.  It also can be used to send posts to Facebook telling your location and that you are OK.  It costs about $150 and the subscription for the email and Facebook posts costs about $150 per year.  A Satellite phone is even better but they cost about 3 times as much.