[scarlac]

The rule makes a lot of sense but most of the articles I found completely ignore if this includes systems like GitHub or Bitbucket. Technically you can create a Pull Request based on the branch yet no-one is actually "using" it. Would you say the rule also applies to such a branch?

[chrisjshull]

I would. A common thing I like to do is start working on top of work that's in a Pull Request. For example, maybe a coworker is adding an API that I want to use. So long as I'm confident the API won't have drastic changes, and there's just smaller polish or testing to be added, I can branch off of their branch and start working without delay. This also gives me a window to live on top of the changes and give feedback from usage even faster (maybe even before it officially lands).