I actually came back from a 2 year break on the very weekend they did this, and OMG, it was so much fun to play the game without having to look for a bloody party!!! They should leave this double XP on all the time. If you can't find a party, or don't even want to JOIN a party, you shouldn't feel penalized for it. I had such a blast leveling a RDM from 0-22 in the space of a weekend. If they kept this on, there'd be a LOT less rage quitting.
Trefan the Taru!