My brother told me about this down the pub one night: If you accidentally lock your keys in your car, you can ring someone with your spare key and unlock the car through the mobile phone. Needless to say, nobody believed him; but he swore that it had actually worked for him.

Me and Mrs KFK decided to try it out yesterday in a big car park: She wandered off until the key fob was out of range and wouldn’t open the car any more, then she phoned me. I held my phone by the car door, and she held the key fob by her phone. She pressed the button, and viola: car unlocked!

So is the unlocking signal somehow being sent down the phone? Or is the phone somehow amplifying the key fob’s signal? I don’t know yet, as we haven’t had time to try it over a larger distance, but this is what Snopes has to say:

http://snopes.com/autos/techno/keyless.asp