Surely almost all publicly available GitHub repos permit making a clone of them in their license?
> [...] and to reproduce Your Content solely on GitHub as permitted through GitHub's functionality
Use, display, and perform through the GitHub Service are permitted according to the GitHub ToS, but not reproduce except on GitHub, unless further rights are granted with a license.
GitHub and GitCode do not provide an easy way to search for these, so you will have to scrape the API and clone the repos to find out the ratio of FOSS/restrictive/no license.
My repos had their open source license available, so I guess we'll need to wait to see actual examples of illicit copies.
I wonder what they do with the user accounts though, might I be able to access it somehow? Or someone else..