Super interesting post!
I'd have mentioned Unit tests as another measure to tackle uncertainty. Simple, boring unit tests (reminds me of this post[1]).
Maybe he just assumes those will exist when professional engineers write code. [2]
Unit tests are of course important, but they don't test for higher level failures like network issues, high latency, increased load, etc. Your components must be designed to be isolated from incidents as much as possible, possibly using the techniques implemented in Hystrix [1], an open source library from Netflix.
Yes, that's absolutely true. Unit tests are super important in order to guard against future mistakes. Or put another way, they guard against the uncertainty of the code maintaining its current functionality in the future.
[1] http://robertheaton.com/2013/04/01/check-youre-wearing-trous... [2] http://www.amazon.com/Clean-Coder-Conduct-Professional-Progr...