Pretty sure they intended for us to not be able to turn it off. If it weren't for the extra software a lot of video card companies provide, and the savvy tips from other gamers, most people wouldn't even know how to shut it off anyway. The fact there is no in-game option for it to be turned off, and that the only setting to turn it off is buried in an INI that most people won't bother with, it seems to suggest they expected it to be on. If you turn it off, you are on your own. From their perspective, anyway.
The worse thing is, their implementation of Vsync going all the way back to Oblivion has caused loads of input lag.
I ALWAYS had to disable Vsync forcibly in my GPU settings, Oblivion, Fallout 3, New Vegas, and now Skyrim.
For some reason, I have always been very perceptive of input lag and latency in general, across all my devices, and I would estimate that by default (Vsync enabled) Skyrim suffers from about 400ms of input lag. Enough latency to make mouse aiming imprecise, for users to consistently overshoot objects in the game world, and seriously hamper the overall sense of being in control.
And EVEN SO:
The game is so poorly optimized that no matter how powerful your system there will be lag spikes that cause your frame rate to go BELOW 60, and cause a decrease in sensitivity.
Unless they played at minimum settings on super computers (to get constant 60p render) this problem would have been noticed immediately by any QA team. In which case Bethesda should get a different firm to carry out their testing as their current provider is clearly inept.
Or the game wasn't QA tested at all on PC; a single programmer the night before going to press, after copy and pasting the Xbox 360 build might have hastily booted it and thought 'This will do' without even clicking past the menu screen.
Both situations are abominable and show, dare I say it, Bobby Kotikian levels of disrespect to their paying customers.
Dear Bethesda, you have lost of the respect of many of your customers by consistently releasing flawed products at launch, but you can win at least some of us back,
Let us know that you are aware of the issues and that you are working hard on a patch.
Every day you leave us in the dark, our respect for you decays.
We can only forgive so much.