Good question. I don't think "Open" and "Free" are the same. Most of the games I have published are Open with a CC license, but they are not free. They are a lot of work, and I spend money on custom Fonts, Artwork and Software to create my games. I need to recuperate this somehow. So to me, open means a license that allows someone else to remix and use my game however they like; they can even sell it because that's only fair if I ask for reimbursement on mine. It would be good to get clarification on what is meant. Past Jams I participated in left the monetary question up to the participants.