Has anyone heard of this scam regarding carjackings?

Beware, it's headed your way.
Just last weekend on Friday night we parked in a public parking area. As we drove away I noticed a sticker on the rear window of the car. When I took it off after I got home, it was a receipt for gas.. Luckily my friend told me not to stop as it could be someone waiting for me to get out of the car.. Then we received this email yesterday:

WARNING FROM POLICE
THIS APPLIES TO BOTH
WOMEN AND MEN

BEWARE OF PAPER ON THE BACK WINDOW OF YOUR VEHICLE--NEW WAY TO DO
CARJACKING (NOT A JOKE)

Heads up everyone!
Please, keep this circulating.. You walk across the parking lot, unlock your car and get inside. You start the engine and shift into reverse..
When you look into the rearview mirror to back out of your parking space, you notice a piece of paper stuck to the middle
of the rear window. So, you shift into Park, unlock your doors, and jump out of your car to remove that paper (or whatever it is) that is obstructing your view. When you reach the back of your car, that is when the carjackers appear out of nowhere, jump into your car and take off. They practically mow you down as they speed off in your car.
And guess what, ladies? I bet your purse is still in the car.
So now the carjacker has your car, your home address, your money, and your keys.
Your home and your whole identity are now compromised!
BEWARE OF THIS NEW SCHEME THAT IS NOW BEING USED.
If you see a piece of paper stuck to your back window, just drive away. Remove the paper later. And be thankful that you read this e-mail. I hope you will forward this to friends and family, especially to women. A purse contains all kinds of personal information and identification documents, and you certainly do NOT want it to fall into the wrong hands.