The studio knows how addictive the MMO scene can be and already employs measures to 'sanction' those who play too much a week. Thanks Square.
Now this shows a company that cares - it knows its product contains such potential awesomeness that your life will be sapped away, which disastrously might prevent you from buying further Square Enix products in the future, what with no job and all.
"Please do not forget your family, your friends, your school, or your work," ends their special message to players. Of course for those with distant family, no friends and workers comp you can play away, or at least for around 15 hours.
After the 15 hour mark within a given week you'll be getting no rewards for playing, which is in place to help keep 'obsessives' from becoming... well, obsessed.