Quite like this comment in the recent slashdot post regarding hardened-php:
as the japanese car makers discovered (or at least the idea came to prominence) in the 1950s, ANYBODY (even people with 93 PhDs) who assembles something makes mistakes occasionally. the trick is to limit the number of modalities that allow for mistakes. a person who is asked to make a wheel fairing in three minutes using simple hand tools will make far more mistakes than one who has a dedicted stamping machine.
in fact, the japanese cars excelled in quality, worker satisfaction, and in the competitive marketplace for many years in large part that their idea that a) errors are natural stochastic processes b) the rate of errors in an any process is more determined by the design of the process than some inherent quality of the worker and therefore c) when a mistake is made, analyze the process, don’t blame the worker as this will lead to d) continuous improvement and also empower workers to speak up.
even the most experienced PhP programmer can make an error. education helps, but fixing the system is a better idea.