Short Range radio alarm

Simple fact- the vast majority of drivers are never more than about 200 yrds/mtrs from their cars. At home, at work, visiting friends, at sport, cinema, shopping- your car is usually pretty close.

So how about a simple single frequency FM transmitter hooked up to your car ignition or existing security system, that transmits a warning beep to your receiver/keyring. The transmitter need not be powerful, expensive, or versatile- just enough to send you a warning. You might just have enough warning to do something about it..

This is not like those fancy mega-thousand$$$ Global Positioning Systems the likes of BMW are trying to sell..