Exactly.

But that's still security-obsessed mindset, and I think this is a problem in itself, because it biases people to see this fundamental aspect of general systems as a problem.

So imagine that, instead of a credible extortion message, you find there credible call for help. Like a post-it, clearly written in a hurry, saying "${employee} is trying to hurt me, call 911".

It would give a pause to any sane person, and perhaps prompt them to consider calling 911 or at least investigating where that message came from. And you definitely wouldn't want a person who routinely ignores such things because "this sheet is labeled <data> therefore I cannot allow it to influence my actions".