Huh, a new design feature of the 737 MAX that *isn't* brain dead: in event of a decompression (as on Alaska flight 1282 last week), the cockpit door automatically opens. Presumably to prevent another crash like Helios Airways flight 522 in 2005. (Aircraft depressurized, crew lost consciousness, cockpit door was locked, FA's couldn't gain access to the flight deck before it ran out of fuel and crashed into a mountainside killing all on board.)
@cstross@goatsarah unfortunately, the lack of telling crews about it has instead led to everyone knowing about it. Including those that might want to gain unauthorised access to a cockpit.