Mythbusters tested the myth that a ceiling fan could decapitate. They proved ceiling fans aren’t strong enough to do that. But, the dummy they used sustained damage. I’d say it was enough to inflict a skull fracture. It could definitely send you to the ER.
Way back in the Dark Ages when I was in the service a very drunk girl climbed up on a table in the O’ Club bar. She was gonna dance.
That lasted about 20 seconds till she hopped just a bit too high & took a fan blade in the forehead. As you’d expect for a forehead laceration, it bled like Hollywood. She looked mortally wounded even though it was just cut skin. She ended up in the base ER with, IIRC, 4 stitches to close the wound. Real buzz kill for her. That night’s party continued pretty much unfazed.
And she gained a reputation as the go-to party girl that took years to live down.
I do not know about a full beheading but we have some old small metal ceiling fans that on the high setting would do way more that just cut you a little.
Also, after the totally stupid cannon ball stunt the ‘M Busters’ just pulled ( Round cannon balls skip like crazy, a long known fact. ) it makes me even more aware of how many things the set up to reach a foregone conclusion.
Fun show but they are not the definitive word on a lot of the things they say they are.