We seem to be missing an off-topic close reason. I think. Unless I'm missing something.
When I select off-topic, I can choose from:
- homework with insufficient research
- fringe rather than mainstream physics
- belongs on math.SE or meta.physics
But there are potentially plenty of off-topic questions which don't fall neatly into one of those four boxes, so I'd have to use the option of flagging a diamond mod with a custom reason. Which seems like overkill.
So I think this is turning into a feature request for a new close reason (one that will also appear on the flagging screen): "this question is not about physics concepts"?