2) A GPS is an excellent tool to tell you where you are.
Unfortunately a GPS isn't a very good tool to tell folks which direction to head off to. i.e. the wrong map datum and incorrect Mag declination information may have made matters worse because the hikers will trust the electronic box to point them in the correct (wrong) direction.
The biggest problem with a GPS is a combination of these factors
- it is so easy and intuitive to use that it undermines the motivation to learn and train basic navigation skills (map and compass)
- the batteries will die (bring spares!)
- a solid knock or a tiny drop of whater in the wrong place is all it takes to kill even the most robust GPS