You will never complete be sure that no leakers get into when its not restricted, but new Members scares that. think like Zab.
But the restricted is the only way when you dont want to have leakers in. Why not optin a day before and Zab send the Usernames to Fulltilt to register?
Isnt that possible? Maybe you can optin till 24 Hours before and all Usernames that optin will be send to Fulltilt to register. I dont know if its possible, but we do in an other Forum so for Monthly 500$ Tourney.