Elder Scrolls IV: Oblivion Q&A

The Oblivion Source has published a Q&A with Bethesda's Pete Hines, in which they briefly discuss the upcoming Elder Scrolls IV: Oblivion. Here's a taste:
Q: "Cyrodiil is not an island -- what have you done to make sure the player doesn't leave the province?"

A: "There is a "border" - you basically hit an invisible wall and the game says "you've reached the edge - go back". So no, there is not infinite water. Cyrodiil is surrounded by the other provinces, so we have to do a border. As much as possible, we try to make this a physical barrier, like a mountain, but that just looks odd sometimes, so we go with the game message. But because you can now see so far, we've had to build miles of landscape into these provinces, because even though you cannot "go" there, you can stand on a mountain and "see" there."