I haven't tried this but let me know if it actually works if somebody else tries it!!! Sounds like a good idea.
What to do if you lock your keys in the car.
Locked your keys in your car ? Did you know this? Good thing to know.
If you lock your keys in the car and the spare keys are at home, call
someone on your (or someone else's) cell phone.
Hold your cell phone about a foot from your car's front windshield, or
dash and have the other person at your home press the unlock button of
your key fob (clicker), holding it near the phone on their end. Your car doors will unlock. It saves someone from having to drive your keys to you.
Distance is no object you could be hundreds of miles away, and if you
can reach someone who has the other "remote" for your car, you can
unlock the doors (or the trunk!).
Editor's Note * It works fine! We tried it out, and it unlocked our
car over a cell phone!
Mike's Note * " I locked the car and had my youngest daughter call me
while she was near the car. I clicked open into the phone and I could
hear the car doors unlock through her cell phone. My daughter
confirmed that sure enough the doors opened."