Old Military Joke:
Q: What's the most dangerous thing in the Military?
A: A 2nd Lieutenant with a map and compass.
Perhaps she'll get lucky and they will return with a GPS...
Not for another few centuries, sadly.
... a Homing Pigeon?
(http://img.thesun.co.uk/multimedia/archive/00124/SNN0517A_124638a.jpg)
That's brilliant.