Re: "t took a few thousand deaths for the airlines to get their acts together."
Not a big deal anyway. The occupants of the cockpit can still choose to block entry even if the code is known:
http://www.independent.co.uk/news/world/europe/germanwings-captain-patrick-sondenheimer-tried-to-break-into-locked-cockpit-door-with-an-axe-as-10138492.html