Great idea if it works.

[Mr. P]

Next time you come home for the night and you go to put your keys away, think of this:
It's a security alarm system that you probably already have and requires no installation. Start keeping your car keys next to your bed on the night stand when you go to bed at night. If you think someone is trying to get into your house, or if you hear a noise outside your house, just press the panic alarm on your car key chain. Test it' It will go off from most everywhere Inside your house and will keep honking until your battery runs down or until you reset it with the button on the key fob chain. It works if you park in your driveway or garage.

If your car alarm goes off when someone is trying to break in your
house, odds are the burglar or 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.
Try yours to make sure it works before you rely on it. Just know that
you must press the alarm button again to turn it off.

And remember to carry your keys while walking to your car in a parking lot. The alarm can work the same way there.....