From what I got it will switch settings depending whether there is a non-member in the game:
If you create a game that uses a member-only feature, such as a low luck level, and invite non-members, the game will simply revert to using 75% luck. This allows you to freely create games without having to worry about this restriction -- the created games will use low luck when the can, and 75% luck when they can't.
Meanwhile, I'm impatiently waiting for the first Custom Tournament to be created
Another question: low luck level is a member only feature except for built-in templates, such as strategic 1vs1 (you can create games on strat 1vs1 as a non-member, but cannot change anything, including open seat prerequisites). Would such a ladder allow strat 1vs1 for non-members?