your not the only one I just got an email today about it and I would presume if u would not choose to back up on icloud or turn off it would still be on game center to answer your question but I am not sure his question is if I turn off icloud for this app will my stuff still be saved in gamecenter????????????????
Idk if it's something someone could do like stock mid and maxed chart so ppl don't get their head beat in buying or selling might make it a little more fair