Rather, it hides a secret function for the shopping cart. When customers leave the Aldi property with the shopping cart, an immobilizer automatically sets in. This is due to magnetic stripes that are hidden in the ground.
Customers can no longer push their shopping cart without problems. Rolling customers with the locked cart over the grooved carpet at the entrance, puts out the lock. So when you come across a locked shopping cart, just roll over the carpet at the entrance.