True, but for those players under contract at the club's leaving they won't need to worry, they'll just carry on playing. The club's will just tear up their current contracts and immediately re-sign them on new ones.
End result is the same sure, but if this new league is outside of FIFAs jurisdiction then the club's don't need to worry about registration at all.
Fair point, any contract talking about a players FIFA registration would be null and void if they were banned whilst playing in the super League, meaning those players could immediately sign for another club.