Most people now have their mobile phones with them most of the time. So it is possible that in an emergency they are able to make a call. However, if they are in a remote area and don't know where they are it can be very difficult to locate them. Even the most skilled map-reader can get lost and/or disorientated in remote country and arduous weather conditions or if injured.
Using the Retrieva Tracker for hill walking, climbing, outward bound exercises, trekking and field trips means that there is a safety locating device that is independent of a the carriers map-reading skills. The tracker can communicate that location to friends or supervisors of the exercise and will enable them to locate the carrier accurately and quickly.