I couldn't help but think what I would do if my wife went missing for some reason on a freezing cold night.
It occurred to me that one easy way to locate someone is to have their mobile phone send back its GPS coordinates, so after reading about this local tragedy Kris and I have decided to install location software on our phones. This software allows me to locate her phone and vice versa. After looking at the options, we selected "Where's my Droid" because it is free, easy to use and is well recommended by the Android community.
We changed the default text commands to random stings, locked the front end with a PIN and stored the PIN and strings in our secure password vault. This allows either Kris or I to locate the other person's phone in an emergency.
Please note: This technology can be used in a seriously creepy way, so if you decide this might be a good idea, be sure you only give the keys to someone who you trust completely.