Never use deadlocking if someone is still inside the vehicle.
If the vehicle is equipped with a deadlocking function, this allows you to lock the opening elements and to prevent the doors from being unlocked using the interior handles (for example, by breaking the window and then trying to open the door from the inside).
Do not store the “hands-free” card anywhere it may come into contact with other electronic equipment (computer, phone, etc.) as this could hinder its operation.