Last week I hit the Valor point cap (1000) and I had the Valor of the Ancients buff. This morning I logged on, and completed the Battlefield Barrens quest which awards 200 Valor points. I honestly cannot remember how many points did I have, but when I checked my weekly limit it showed that I had already reached 300/1000.
The other odd thing is that I still have Valor of the Ancients buff, considering I have no other characters with capped Valor points. My question is, is this a glitch that my cap is now at 300 or did I gain extra Valor due to my buff?
Edit: I should add that as of 10/7/2013 this does not happen anymore as the Valor of the Ancients Buff is not available when logging in after a reset. (I tried this today and got the 200 valor promised by the quest).
Best Answer
You gained the extra valor because you still had the Valor of the Ancients buff.
Why you still had the buff? Well, it seems that when you log-in after the reset, you keep the buff. It isn't checked and removed until you encounter a loading screen.
Therefore, if you are in Kalimdor before the reset, when you log-in next, you can finish the Battlefield Barrens quest and receive the extra 100 valor points (just don't do anything which will give you a loading screen).
Also, as you can collect the supplies for that quest without having the quest itself, you can farm enough, to be able to turn it in straight after the reset.
The same trick can be done with daily quests in Pandaria or Isle of Thunder. Not sure of the possible valor for completing each daily quest though. But remember you can only do one zone (Kalimdor, Pandaria or Isle of Thunder). In terms of least effort, Battlefield Barrens is the easiest.
Remember not to use any portals which quests might give access to.
Hope that helps.