Thinking through all of this is what has led me to our current intent to open-license all of Ars Magica.
First of all, I believe that fans of the game want to spend money on their hobby, and I think we can find ways to make them feel good about giving us that money. Yay!
But secondly, I want people to create awesome things. Honest self-reflection tells me I have actually been a barrier to that. Given IP law, it's not enough to wink and ignore things that someone in the future might sue over.