I get it. Again, the point is, so what? Take the measurement and alter the outcome. Or decide you're the one being the baby and keep the plans.
But in general, aren't there some cases where we want to moderate our communication based on how it will be received? Honesty is the right default, but not universally correct.
The classic example is that it might be preferable to tell someone that a dress they just bought looks good on them.
I think as children we tend to be too honest, and then overshoot as teens or young adults by worrying too much about social acceptance. And we have to find a middle ground.