http://forum.square-enix.com/ffxiv/t...s-Restrictions
Resolving AFK Character Issues
From several users on some of our more congested Worlds, we have received requests for a feature which automatically logs out characters who are AFK for an extended period of time. We are actively looking into the implementation of such a feature, but have decided to first concentrate our efforts on increasing the number of Worlds and optimizing the Duty Finder servers.
They seem to be pussyfooting around the issue. Don't get your hopes up for a AFK fix anytime soon. They'd rather try their luck with "increasing server capacity." We'll see how well this goes in the coming days.