afaik Shepherds author also had a deal, before transitioning to Twine at least. But to me, these deals always sounded like something decided on a case-by-case basis, not just "ask and ye shall receive". Still, if they were to really push it, it would just get a bunch more people to transit to Twine.From what I've heard CC has deals with them
It simply isn't practical for them to enforce it, I guess.