I feel like that would be counterproductive given that GitHub is a tool, not a social network you need to gather account age or fake internet points on to use. Don't really see anything wrong with somebody signing up and immediately creating a PR.

I realize GitHub is one of the most popular choices out there but the activity stream is already social mediaesque enough for my taste. There's other ways to tackle this, DO could make their marketing stunt opt-in and GH could respond to the people wanting to add friction to their repo's workflows in a way that provides value, without crippling the general user experience.

I think this would be a bad direction. I bet that most people create an account on GitHub to report an issue or create a pull request directly. I think this should be encouraged.