When I have a question to ask about the Tekkit pack for Minecraft, should I tag my question with both minecraft and minecraft-tekkit or just minecraft-tekkit? Speaking from my experience with StackOverflow, we specifically discourage tagging both java and android in one question, as the question rarely has anything to do with Java itself.
We do tagging a little bit differently, here on Arqade.
The only rule we've been able to consistently agree upon, is that the game the question is about should be one of the tags.
From my understanding, Tekkit adds a whole lot of stuff onto minecraft, but it's still about placing blocks.