Faction Points and NPCs / Quests

Can someone please help me out with this.

And if this has already been discussed on guru (i cant find it), please dont flame me, just helpfully point me to the thread.

I recall reading (somewhere) that if you have a lot more points in one faction than another, that some NPCs of the faction you have less points in, wont talk to you.

I'm guessing then that if i have as an example, 5000 Kurzick and 0 Luxon that the Luxon NPCs wont talk to me. I also assume from this that I cant take the Luxon quests that those NPCs would normally give me.

So, my main question is this :

If I happily complete Kurzick quests, and lets say finish the game with the Kurzick route, and I then spend all my remaining Kurzick points on the crafting material, bringing me back to 0 faction points for both factions, will the Luxon NPCs then talk to me.

Meaning, that I can then go off and do all the Luxon quests that I missed first time around, as they should now talk to me.

Or am i missing something.

I really want to be able to say I've done all quests / missions.

This happened to me while I was playing in the Beta Event. I found that after about 500 faction worth of difference, certain vendors wouldn't trade with you anymore. I also found that I could still do quests, regardless of this. But, yes, you should be able to spend your Faction points to be able to do the quests for the other team, if that is your desire. I don't believe that one side will be locked out completely and irrevocably just because you did some quests. Especially since the Faction is universal for that account.