That's actually a really interesting parallel to draw. I have certainly seen a non-negligible amount of dishonest management ("Sure we'll promote you, we just need a few more cycles" to a friend who was about to be fired). From a legal perspective I'm sure what's signed in writing makes the difference.
But we're not really talking legal here, we're talking ethical. And ethically, I'm not sure why dishonesty on paper is worse than dishonesty in a 1-on-1.
You'll find all kinds of notions/norms in our culture that are inconsistent with each other. Usually it takes a standup comedian to point out our own hypocrisy.