Every big bug I have seen has been known by a developer and not ticketed and triaged. Apathy, sometimes, ignorance more often, lack of organization, almost always
I'm hoping we'll eventually be able to flag bugs with the types involved, and let systems automatically look for combinations that have a set of types that could be dangerous.
My point was that it's not enough to focus on good intentions -- or culture -- you have to talk about mechanisms and technologies if you want a reliable system. Because the parts, humans in this case, are highly unreliable in isolation.