This also happens with garage door remotes.
How to Lock Your Car and Why

I locked my car. As I walked away I heard my car door unlock. I went back and locked my car again, three times. Each time, as soon as I started to walk away, I would hear it unlock again!! Naturally alarmed, I looked around and there were two guys sitting in a car in the fire lane next to the store. They were obviously watching me intently, and there was no doubt they were somehow involved in this very weird situation. I quickly chucked the errand I was on, jumped in my car and sped away. I went straight to the police station, told them what had happened, and found out I was part of a new, and very successful, scheme being used to gain entry into cars.

Two weeks later, my friend's son had a similar happening.... While traveling, my friend's son stopped at a roadside rest to use the bathroom.. When he came out to his car less than 4-5 minutes later, someone had gotten into his car and stolen his cell phone, laptop computer, GPS navigator, briefcase.....you name it. He called the police and since there were no signs of his car being broken into, the police told him he had been a victim of the latest robbery tactic -- there is a device that robbers are using now to clone your security code when you lock your doors on your car using your key-chain locking device..remotely. They sit a distance away and watch for their next victim... They know you are going inside the store, restaurant, or bathroom and they now have a few minutes to steal and run. The police officer said to manually lock your car door-by hitting the lock button inside the car -- that way if there is someone sitting in a parking lot watching for their next victim, it will not be you.

When you hit the lock button on your car upon exiting, it does not send the security code, but if you walk away and use the door lock on your key chain, it sends the code through the airwaves where it can be instantly stolen.

This is very real.

Be wisely aware of what you just read and please pass this note on.. Look how many times we all lock our doors with our remote just to be sure we remembered to lock them -- and bingo, someone has our code...and whatever was in our car..

Snopes Approved --.Please share with everyone you know

Originally Posted by rkadcock

I know that they have been "immune" since at least July when I got my Clifford (made by the same company that makes viper). I don't know for sure if they're a 100% immune but they use logarithms that change everytime you lock/unlock your car thus changing the code. However you can mess up that safety feature by unsynching your remote with the alarm. Hitting random buttons on the remote while not in range of the vehicle "unsynchs" the logarithms thus making it possible for someone to steal your code.