The original repository you have to fork (github/game-off-2012) is public. You can't make forks of public repositories private, so you're right.

The nice thing about git is that it is distributed. Meaning, you don't have to push to your public fork until just before the deadline if you concerned about your ideas being stolen.

If you are afraid that your idea will get stolen, don't participate. If its that good, it still will be stolen at the end.

I don't see a reason to be afraid about stolen ideas. The way i see it you would enter something like this just for the kicks....not for the prizes..and it's not like the prizes are millions..soo.. :)

However, (having not read the rules) I assume there's nothing stopping you from committing an obfuscated/minified/compiled version if you care that much.

Why comment if you cannot be bothered to read the four rules?

"All entries must be web-based, i.e. playable in a browser. HTML5, WebGL, Unity, Torque 3D, Node JS, Flash are all possible - just be sure the source is made available on your fork."

Obfuscated/minified source is still source. I read that part you quoted.