They didn't do global rollbacks I would assume since the "bug" occurred the day before Underfoot launch and that would have been
Ironically, I got "better-than-expected xp" in a zone I had never successfully killed a mob in before (makes it hard to know what you are supposed to get, though I was suspicous if it was hotzoned early or something as it seemed very nice). After a while of grinding and enjoying it, the zone was taken down (at first I thought the whole server was coming down, but that was not the case).
Anyways, they wiped about a week (and an active one at that... sigh) from my character as they did the roll back 6 days after the "heinous" incident. While I think it is stupid that they would bother to roll back anyone at all, I do find it extremely annoying that they 1. didn't talk to be about it. 2. have called me an exploiter when I asked about it via petition and 3. didn't have the precision to take away the "extra" xp from the zone they put up with more than it should have.
A GM saying to me "Hey, that zone was bugged and you got __% more xp than you should have, we are going to adjust it to what you should have got... well I would have no complaints.
Of course a smarter company would send me a letter: Merry Christmas valued SoE customer. We hope you enjoyed your extra xp. We recognize that your gimp little character isn't going to unbalance the game having had a the benefit of our little error. Happy holiday, your buddies at SoE
I suspect quite a few old school players away for the holidays will come back and find themselves rolled back.