Another productive idea: allow github repos to come without "pull request" button - that's the one feature that can't be disabled, but for various projects that would be exactly the right thing to do: the "it might be useful to others, but for me it's done" projects just like those using github as mirror (because people desperately need the fork button).

But it doesn't make immediate business sense: projects not using pull requests don't buy into the platform. Amazing enough that the bug tracker can be turned off...