Pretty neat idea. Never thought of it before. Put your car keys beside your bed at night. If you hear a noise outside your home or someone trying to get in your house, just press the panic button for your car. The alarm will be set off, and the horn will continue to sound until either you turn it off or the car battery dies. If your car alarm goes off when someone is trying to break into your house, odds are the burglar/rapist won't stick around. After a few seconds all the neighbors will be looking out their windows to see who is out there and sure enough the criminal won't want that. And remember to carry your keys while walking to your car in a parking lot. The alarm can work the same way there. Maybe it could save a life or prevent a sexual abuse crime. Would also be useful for any emergency, such as a heart attack, where you can't reach a phone.