Car thieves use relays -
"They basically use relay devices to capture and boost signals from the fob. For instance, when the car is parked outside your home, thieves can come with a relay device and waive it outside. If the fob is inside the home, they will be able to pick up the signal." Sep 25, 2023
"Only cars with a keyless entry system can be stolen using so called “relay” equipment. Keyless entry cars allow the driver to unlock and start the car with the key fob still in their pocket. Once in the car, the driver can press a button to start the engine."
"How far do relay devices work?
What Is Relay Attack and How To Prevent It
A relay attack usually involves two people working together. Thief 1 stands by the targeted vehicle, while thief 2 stands near the house with a device that can pick up a signal from the key fob. What's more, some devices can pick up a signal from up to 100 meters away."
https://www.youtube.com/watch?v=6_8i8bemhFw
You're sitting in a restaurant, & your key fob is constantly giving off a signal. One thief can sit near you, pick up your signal, & relay your key fob signal to the second thief outside by your car. The second thief can enter your car & drive off with it.