so I have a beer or two and am just over the limit where the car won't start anymore, but then suddenly space aliens with anal probes arrive
And one tells the other, "Lookit Bubba, 'dis one's drunk already. Let's get him."
As for your other two examples, your car can fail at any time. I don't know about the reliability of the proposed devices, but I'm not sure people blame auto makers when the car needs to be started and it won't for some reason (dead battery, whatever).