As part of a post mortem you should ask "People will remain fallible; How can we change the process so this is unlikely to happen in the future?" And in genera

As part of a post mortem you should ask "People will remain fallible; How can we change the process so this is unlikely to happen in the future?" And in general one likes to see that kind of transparency ... but if the the problem is someone snuck through our defenses, often we don't want want to publicize the changes made because it might help the next person. Although a "Steps will be taken." might be nice.