Account creation & dubious account mechanics.
So, apparently Square Enix uses a similar "parent account" system to WoW. However, according to information from http://www.dualshockers.com/2013/08/10/heres-how-final-fantasy-xiv-a-realm-reborns-free-30-days-for-pc-and-ps3-and-welcome-back-campaign-will-stack/ it's unclear as to whether you will receive your free month of game time for each service account if you register multiple PC codes on the same parent account.
Also, according to the Square Enix FAQ at http://webcache.googleusercontent.com/search?q=cache:yFKJGNy50gUJ:support.na.square-enix.com/faqarticle.php%3Fkid%3D56910%26id%3D902+&cd=2&hl=en&ct=clnk&gl=au&client=firefox-a, they apply penalties and such to parent accounts, not service accounts. So any infractions on any of your accounts will result in all of your accounts being disciplined.
Seems like, although it's more convenient to have all of your accounts linked, it's both safer and more cost effective to register four separate accounts to avoid possible issues.
Basically, you will get 30 days of game time with your copy of the game only if you register a new platform that you don’t already have, meaning that if you played the original Final Fantasy XIV, purchasing the new PC version won’t do you any good, because you cannot register it, since you already have an active PC service account. On the other hand, if you purchase the PS3 version and add it to your old PC service account, not only you’ll get your free 30 days, but you’ll also get the “Welcome Back” bonus, meaning that your new 30 days won’t be counted down until September the 10th.
If you’re a completely new player and you purchase both the PC and the PS3 versions and register them both to the same service account, you won’t just get 30 days, but the two versions will stack up to 60 days.
Also, according to the Square Enix FAQ at http://webcache.googleusercontent.com/search?q=cache:yFKJGNy50gUJ:support.na.square-enix.com/faqarticle.php%3Fkid%3D56910%26id%3D902+&cd=2&hl=en&ct=clnk&gl=au&client=firefox-a, they apply penalties and such to parent accounts, not service accounts. So any infractions on any of your accounts will result in all of your accounts being disciplined.
Any service accounts that are associated with the same service as the suspended service account will also be suspended (see: banned).
For example, if you have a Square Enix Account with multiple FINAL FANTASY XIV service accounts and you receive a suspension on one of the FINAL FANTASY XIV service accounts, all other FINAL FANTASY XIV service accounts will also be suspended. However, any associated service, such as the Account Management System or SQUARE ENIX Members, will still be available to you during the suspension period.
Seems like, although it's more convenient to have all of your accounts linked, it's both safer and more cost effective to register four separate accounts to avoid possible issues.