What are the specific responses and safety mechanisms of a car equipped with a keyless ignition system if the key fob is thrown out of the window while the vehicle is in motion? Please explain how the car's system detects the absence of the key fob, the steps it takes to ensure safety, and whether the vehicle will continue to operate normally or initiate a shutdown procedure. Additionally, include information on the potential warnings or alerts that the driver might receive and how different car manufacturers might handle this scenario.