Ask HN: What is your company's policy around using GitHub for personal projects

In our company we are having a debate about our opensource contribution policy. One of the Items being debated is "Should developers be allowed to create their own repos on github?"

I'm strongly for developers being able to create their own repos for personal projects to tinker.

HN, can you tell me how companies like Google, Facebook, Twitter, Netflix deal with developers creating their own repos for personal projects on github. What are your company's policy around it and is there a policy in place.