Ragnarok.Yatenkou said:
»They can't ban your FF14 account for something that happened in FF11. Why? Because you agreed to 2 separate terms of services, if you only broke the ToS on one game, you aren't eligible for a ban on the other game due to not breaking the other game's ToS.
They cannot legally do this, and if they have no evidence to prove that you broke the ToS in the other game, then you could hold them legally liable as a ToS agreement is a contract, and they break their contract by banning you for something that has no impact on that ToS you agreed to.
So in short, if they banned you in FF14 for something you did in FF11, they are not allowed to do that and could get in trouble.
All terms of service clearly state that they own the intellectual property and can terminate your service for any reason at any time. They can ban all your game accounts and your SE account because they don't like the color of your eyes.
Yes, being banned in ffxi could get you banned from ffxiv, but it's unlikely.