Without the intention to sound hostile, could you enlighten us on how it does not fit the lore for several Nords to have a barbrawl, or how it does not fit the lore for a bandit to rob someone?
Even, if not especially in War, these events happen. Vampires will be playable, how will people respond to the spawn of Molag Bal?
With a friendly pint of mead, or with distrust and possibly open hostility?
Is it lorewise correct to try and decapitate an Altmer in Cyrodiil, but suddenly not lay a finger upon him as soon as you encounter him across the border?
If we purely regard lore and immersion, I would say you needed to vote for a confident YES!
But perhaps I am missing something, and I would appreciate you elaborating.
That said, a discussion was held over here: http://www.gamesas.com/topic/1470714-adding-ffa-pvp-to-the-mega-servers-a-solution/
And within it, also the reasons I personally voted yes for the idea, though I am strongly of opinion that no new content should be designed for the alliance zones in regards of free for all pvp.
Doing such would draw attention away from Cyrodiil.