[Symbiote]

> Right, you set origin to the branch you own

That's surely equivalently complicated as adding a second remote.

Almost every pull request I've made to a project on GitHub has started with a "git clone http://github.com/example/example.git", since they start with bringing down the source code and finding the bug in the project. Sometimes it's something I can fix, so I then need to fork the project on GitHub, add a remote (or replace origin with my fork's location), and make the commits.

That's not too difficult, but it's not easier than sending a diff to a mailing list. If any discussion is necessary, it's easier to keep track of that on GitHub. It's also much easier to see the patch 3 years later, if the maintainer wasn't interested — that's the big feature which makes GitHub (or its competitors) worthwhile to me.

(A long time ago I sent a patch to Git itself to the Git mailing list, and it was about 6 months before it was applied. However, it was applied, so they must have had some way of keeping track.)