This sounds impossible, but.... it actually works! I tried it out and it DID work.
For those of you who have a car or truck that can be unlocked by a remote key fob on your key ring, this may save you time and trouble. If you lock your keys in the car and the spare keys (with your other remote key fob on them) are at home, and you don't have "OnStar," here's your answer to the problem.
If someone has access to the spare remote at your home, call them on your cell phone (or borrow one from someone if the cell phone is locked in the car too). Hold your cell phone about a foot from your car door and have the other person (that you called) at your home press the unlock button, holding it near the phone on their end. Your car will unlock. 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, or have the "horn" signal go off, or whatever!)
Apparently, the radio wave sent out by the remote transmitter on your key fob remote will piggy-back on the cellular wave signal generated by your
cell phone. I don't know how it works or why but it did work for me and my wife so I thought I'd pass this on to the group just as an FYI.