This lovely prank was passed on to me by an upstanding member of the that community of wackos known as stagehands. Yes, the stagehands. I'm sure you have heard jokes about stagehands such as:
Two stagehands are standing around when one of them turns around and squashes a slug thats crawling right being him.
His co-worker turns to him and says, "Why the heck did you do that?"
The stagehand replies, "oh the damn things been following me around all day!
I am sure if you researched that joke, you would find it was written by a stagehand. As a group they are quite a group of pranksters. It takes a better man than me to hang around backstage doing what needs to be done to keep the group of primadonnas on stage from looking any worse than they already do and refraining from pulling some stunt that makes the actor look bad. However, that type of self control is hard to maintain and you have to blow off steam somehow, so stagehands have turned to pulling pranks on each other to blow off steam and what better way than to do to the new guy what everyone else did to them when they first started out.
Since everyone wants to get into show business, there is an endless supply of greenhorn stagehands, lighting designers and scenery designers. They hand a tendency to ask for the impossible, such as anchoring a light to a non-existent grid, or hanging a backdrop where there is no place to hang it. An experienced stagehand knows what to do in this situation. You tell the person to use a sky hook. You know, a hook that just hangs from the sky where there is no rigging point.
I know this sounds very silly, if not absolutely stupid, but a great many people end up falling for this prank and design a set with the idea they can just use a sky hook.