Right now, there are accounts that seem to just fork a bunch of repositories and then do nothing with the forks. This makes those people look like massive contributors to open-source because GitHub gives them a nice "Contributions" tab with a list of popular projects under it.
They also get free advertising in reverse because they automatically appear as a "Member" of the parent project's network, despite having done nothing at all in the project!
At the very least, GitHub should require the forking person to have made some pull request that was accepted. If those forks aren't actually contributing, they shouldn't even be mentioned as a sub-network of the original (except perhaps as an option for the project maintainers to see, if they're curious where forks have occurred).