Terrifying. Imagine being a roofer or other worker when a delivery drone knocks your ass off the n-th floor surface that you're working on. It wouldn't take much to get somebody killed in such a precarious situation.
At a leisurely 3 mi/h, wolfram alpha gives this amusing comparison: about 0.36 times the momentum of an American football player moving at a speed of 1 m/s.
“I will not be hit by an 80 pound flying missile” is a reasonable expectation for construction workers
When I was a roofer, I think we might have used safety lines and harnesses twice, when the pitch was too steep.
It does seem best when using lag bolts to secure such an anchor to the roof but even when not screwed to the roof should provide some level of fall safety.
Even with all the gear, an unpredictable 80 lb object hurtling towards you is a major problem. Not to mention becoming a problem for any standing below.
Was working for a construction guy I overall respected, and he had us going up on a 3-story barn roof without any kind of roped-in protection. Although I was a fairly experienced rock climber (or perhaps because of it), I quit at lunch.
I was very lucky to have had the opportunity to have the backup finances to be able to afford to quit.
Certainly harnesses and other safety gear are much more common in many situations.
Whether or not it's true, if significant numbers of crews believe this they won't be wearing harnesses on low roofs.
With the appropriate amount of sarcasm: the Mayflower included several variations of "stock" and countless untold mistakes in the wake! We surely beat those Soviets and Socialism, gosh darn it. Just don't pay attention to the social fabric or what the CIA has done. Nevermind the particularly Aryan scientists, where we found them, or what might happen when they get fat/bored/lazy and procreate. We need The Bomb.
Long way to say the absurdity is the joke/point.