How does one do this without appearing incompetent?

It doesn't have to a mistake, it could be any other detail that you know would be disagreed with.

Comedy sketch writers would write a throwaway that was too off the wall to air, then include it in their proposal among others to make sure their darlings made it through.

I'm also reminded of the story of the Tetris contract in which a revision of the contract had an important change of a few words, and also an increase of some other fee. This fee change stole the attention and hid the other more insidious revision.

> It doesn't have to a mistake, it could be any other detail that you know would be disagreed with.

A friend's father who was an architect used to do that all the time. He'd submit a drawing that definitely wouldn't pass planning regulations, then go for a meeting with the planning officer and say "Right well how about we swap the swimming pool I am allowed to have, for the dormer windows that I'm not allowed to have?"

Given that even down south here at 56°N no-one really bothers with having a pool, it's an easy trade.

My late father solved the "getting round the planning department" thing by simply being the only person prepared to keep welding new floor pans into the local head planning officer's string of rusty old Opel Manta GTEs...

One more reason to opposed planning departments - too often they are focused on the wrong things. They need to ensure the fire department can rescue people if there is a fire. If my house has a dormer - that should be a first amendment free speech issue they have no interest in (assuming it is otherwise safe). However the looks are easy for someone to verify, while the important things need an engineer to spend time.

Okay, so no planning regulations at all?

So if I buy the plot of land in front of yours and want to build my house as a 40-metre tower of rusted Cor-Ten steel with 1kW floodlights every metre or so, you'd be okay with that?

You have a responsibility to not spill excessive light or other polution to my property. Otherwise yes.

The version I heard involves a 3d artist adding an obnoxious fairy flying around the character, so not critical, but noticable.

I also think the idea here is to apply it to bosses who's self-worth seems to be tied to putting their mark on the product without being burdened by knowledge. (Because they'll want to change something regardless of the state)

You just gotta pick mistakes that are plausible. The point is whatever you do the "bad boss" will find something.

The very competent can do this without the boss realizing ;) Or it's just a tall tale.

Spellcheck is a thing…

One strategically misspelled word placed somewhere around and neer the lower right of the page…

At least that’s the way some lawyers I know do it.

You have a typo there!

Everyone is incompetent, at least situationally.