GM recalled the Chevy Volt a year+ ago to solve this issue, if your car sits not moving but on for more than 90 minutes it turns itself off. This is really only a problem if you can't hear the engine or read the gauges to see the engine is still on. In the case of the volt the gas motor could start to charge the battery if left on once the battery was low(even days later), so the 90 minute thing should solve the problem.There have been well publicized cases where people have failed to turn their car OFF with the push button and later died from CO piosoning in their homes. In fact Chicago just gas one a few months back. Why is it so hard to turn a key???
Reality is though if you are driving and not making sure your car is actually off when you park it inside its your own **** fault if you die from the exhaust gasses. Isn't this how evolution works? Only the smart survive.
I also think in a few years push button start will be standard on all cars, eliminates any user caused ignition issues, like using too heavy of keys(cobalt anyone?). I see 2017 GM added push button start to the Sonic LTZ as well as the 2LT 2016+ Spark. Sorry to say but all the expensive GM cars with keyed ignitions feel cheap when I can get push button start standard on entry level cars with other brands. So much more convenient and increases my safety when I walk to my car with an arm load of grocery's not to have to waste timing fumbling to dig out a key from my pocket.