An idiot is an idiot, keyless-go is a system that has been, to my knowledge, an ongoing tradition beginning within the abouts of the Mercedes SL-Series from early 2000's, so why is this news? Clearly if you leave whatever ICE vehicle on without noticing that you left the engine running on in a closed garage, you can die from CO2 poisoning.
Although a mechanism that shuts the engine off after a few minutes of idling can be useful, it can increase the costs or lead into unwanted situations.
I've never left my engine off like that and probably never will. I don't know about every country's rules when it comes to taking a driving license but in my country's, it's written in the books that one should check the car every time he or she enters and exits it, and 2 grams of brain would tell you the same.