The phone picks up audio signals through a mircophone, it has no capacity to pick up radio waves, it also emits through a speaker.
This can't be possible, but if you wanted to win twenty pounds down the pub, get the row going, take the dough and then do the demonstatration taking care to elaboratley explain to your wife where the spare keys are etc.
A trusted third party holds your original keys.
Demonstrate that this works down the phone.
Keep the money.
Oh, and make sure you get the other keys back off your mate who was with you and doing the real unlocking.