The modern versions of these keys cannot be cloned, they are challenge response. So you need to relay the challenge from the key, and then relay the response from the key back to the car.
This is often used by thiefs who bring the relay close to the front door, hoping for the keys to be in a bowl or a hook near the door. Then they can open and start the car using the relay. The car then won't turn off when it loses connection to the key (because that is dangerous) which allows stealing of the car.
There are cases where this was done over much larger distance, but those attacks are more easily defeated by having tighter tollerances on the latency of the reply. The latency tollerance does not do much for the 'keys near the front-door' attack, which is what the 'stationary keys do not reply' solution is aimed at.
This is often used by thiefs who bring the relay close to the front door, hoping for the keys to be in a bowl or a hook near the door. Then they can open and start the car using the relay. The car then won't turn off when it loses connection to the key (because that is dangerous) which allows stealing of the car.
There are cases where this was done over much larger distance, but those attacks are more easily defeated by having tighter tollerances on the latency of the reply. The latency tollerance does not do much for the 'keys near the front-door' attack, which is what the 'stationary keys do not reply' solution is aimed at.