I think you're right, although I've noticed that there's a timeout where newer cars automatically turns off if the key fob doesn't come back within range after

I think you're right, although I've noticed that there's a timeout where newer cars automatically turns off if the key fob doesn't come back within range after so many minutes. Probably a safety feature to avoid accidental walkaways, whereas the button required a deliberate two-step action (hold down while turning and removing the key) to activate the feature.