I concur with the magnetic key holder idea, my UNGO by Clarion alarm system has an automatic lock once moderate vibration is felt in the car (alarm assumes car is moving and locks the doors for safety)

Well I have had this happen to me 2 times, but I had my key hidden up....wait....In my venus fly trap.....and I was able to get in it.

Once in a Best Buy parking lot, once in my driveway


Do it, it saves you.

E0 #4384 of 6535 Born Jan. 9 1998 My SVT from the ashes 147,466 miles, purchased Nov. 2002 @ 76,559 miles