I agree with the "blackbox" metaphor 100% but you have to bare in mind that we all have blind-spots. Sometimes they're due to the path we took into our profession, eg different education/training routes; and sometimes due to the way we've specialised, eg the example I'd given about how specialised knowledge that isn't recalled frequently can be forgotten over time. Sometimes it's just because there's so much information to take in that our leaky brains missed that specific detail in lessons. However the fact that the author literally did research that "blackbox" -- hence the article being written -- should be an indicator that she is actually a pretty decent engineer.

I find criticising people for having blind spots that we might consider obvious isn't a great way to share knowledge. Not only does it make individuals less willing to come forward with questions but it also means they're less likely to correct your errors (we are all fallible) for fear of being chastised again.