>But this is a matter of degree. This is it. I don't understand why this isn't higher up in the discussion. Do you check whether your brakes work every time b

>But this is a matter of degree. This is it. I don't understand why this isn't higher up in the discussion. Do you check whether your brakes work every time before setting off? Do you check whether your wheels are attached properly every time before setting off? There are a million things that could break on your car. They're just very unlikely to happen. Pilots/maintenance crew for planes checks that kind of stuff for virtually every flight. We accept this small risk with cars. In return we get an enormous increase in efficiency. If everyone had to do a 5 minute check on their car every time before setting off, then that would be a lot of productive time spent on it.