This is pretty popular. Very close to Parkinson's law (or Law of triviality). There is a famous developer anecdote regarding this for Interplay's Battle Chess, which was simply coined "A duck".
A feature added for no other reason than to draw management attention and be removed, thus avoiding unnecessary changes in other aspects of the product. I don't know if I actually invented this term or not, but I am certainly not the originator of the story that spawned it. This started as a piece of Interplay corporate lore. It was well known that producers (a game industry position, roughly equivalent to PMs) had to make a change to everything that was done. The assumption was that subconsciously they felt that if they didn't, they weren't adding value. The artist working on the queen animations for Battle Chess was aware of this tendency, and came up with an innovative solution. He did the animations for the queen the way that he felt would be best, with one addition: he gave the queen a pet duck. He animated this duck through all of the queen's animations, had it flapping around the corners. He also took great care to make sure that it never overlapped the "actual" animation. Eventually, it came time for the producer to review the animation set for the queen. The producer sat down and watched all of the animations. When they were done, he turned to the artist and said, "that looks great. Just one thing - get rid of the duck."
This is the version of the story I was aware of, interesting to read about the much older hairy arms...
When I worked in advertising, the same thing was known as a blue boat. Stick a blue boat somewhere in the shot, and give the client something to remove. It didn’t have to be an actual blue boat, but things that were added for this purpose were called blue boats.
Back in the day before web design existed, we used to use this technique A LOT in print design.
Classic examples were making the type and/or logo a touch smaller than we knew the client would would be comfortable with so when they inevitably ask for these elements to be bigger, we'd be like 'Yeah no problem!'.
Come to think of it, not much has changed...I still do it now (c: