There was some getting used to when I went from my Mustang old style key ignition to a keyless, key fob in my Hyundai import. You kind of have to 'retrain your brain' and realize that all you have to do now is have your key fob with you, in your pocket, when you get close to the car and finally enter it, there is no need to remove it from your pocket until you exit the vehicle for, work, shopping or the evening and lock the doors.
Until I read about this so called 'danger', I never gave this issue a second thought. Not to sound mean or anything, but the people complaining about keyless, push button ignitions are old or older drivers who are accustomed to putting a key in the ignition for most of there adult driving lives.
I compare this to, older drivers tendencies to use the driving excuse "I meant to use the brake", when they 'accidentally' crash into a building or a group of pedestrians by pushing on the accelerator instead. You cant sue the manufacture for not creating a fool proof, accelerator or brake system. Some manufactures, like Volvo, are experimenting with front 'crash sensors' that will stop the vehicle if it senses the driver is not going to depress the brake in time before rear ending the vehicle in front.
I think the keyless ignition system is not "fool proof" enough for older drivers because they're not used to it. I don't hear younger, or experienced drivers complaining about the key fob. I love the convenience. I have already had to replace the battery in one of my fobs. The fob also comes with a manual key in case the fob battery dies while your car is locked. Then you use the cars 'fob jack' to start the car.
I am not sure what kind of 'safety features' could be added for people who "forget" to push the ignition button off. If you walk away from the car with your key fob, and your car is still running, your car will sound an alarm. The problem might be that you leave your car running, lock your doors, while you leave your key fob locked in the car. Now you have locked yourself out of your, parked running vehicle which nobody could steal anyway