The structural engineer doesn't get any gray hairs from that. It's his job. A few more irons and that's that.
Not quite. The "few more irons" also need their concrete cover, making the ceiling heavier again and then requiring even more colleagues for it, you have to treat yourself somehow. All of this is doable, no question—but equally avoidable. If you want to, it can be worth the effort. But usually—and I think also here—it's simply layman’s recklessness. The typical builder distinguishes floor plans at most by "more or less tasty" and just bulges them out where they would otherwise be too tight. So you just point it out sometimes.
