if you make a copy of your key and use the copy to unlock your door YOU STILL HAVE THE KEY THAT WILL WORK IN THE EGNITION INSIDE THE CAR!!!! all someone has to do is break a window and they have a brand new car to joy ride then strip before you get out of the water...
Eh..... good point.... but how would anyone know that your real key is hiding underneath the mat of your trunk or inside your smelly shoe ?