Recently a user made a post on Worldbuilding about making a flying saucer in real life stating that he was told to go to Worldbuilding by a user on Physics Stack Exchange. Unfortunately I don't have enough rep to view the original deleted question or the comments on it, but it was decided that the question did not fit on Worldbuilding because it is about real world problems.
This is of course an issue. Neither site wants to have questions that don't fit it. I'm not sure if there were other issues with the original question, but on both Worldbuilding questions there were numerous other issues. Is there a reason these opinion based/improper/IRL questions get redirected to Worldbuilding?