I recall their response being very human, warm and encouraging, but it also included all of our original sketches, with a very direct (but kid-understandable) statement that they were obligated to return the originals to make it very clear that they were not kept and thus could not possibly be understood to be "inspiration" for anything that might be in a future game.

They told us they took care to not even read the manuscripts. I don't remember if they return them unopened or destroy them, but otherwise if the ideas from the manuscript end up in one of their productions, they open themselves to legal trouble. It may happen even if it is a coincidence, so they don't want to take any chance.

I mean it can work; especially for smaller studios, community members and modders are often hired to work on the game itself (I'm sure Bethesda has a lot of that, the modding community is basically free onboarding / training, but also Factorio's Space Age was mainly inspired and executed by the developer of the Space Exploration mod).

Edit: no dice!