One that helps thieves break into your car and steal you blind in seconds.
If you want to read the entire post please go to Thrifty Ways and Ideas.
Straight from the post:
How to Lock Your Car and Why
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. They sit a distance away and watch for their next victim. They know you are going inside of the store, restaurant, or bathroom and 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 stolen. Something totally new to us...and real. Be aware of this 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 the car...can be stolen.
So, if you are like me you have been guilty of hitting that button to make SURE you locked it while wresting with a kid and getting out your purse, and throwing the toys back in the car because you can't take them in the store......
Not a good idea.
Use the lock on your doors friends.