Me too but that's what I was told last night.........
Can see how it might happen - easy enough to get Arsenal membership online, someone then decided prior purchase history not needed for a European game, lots of the process outsourced to some kind of call centre (like ours is) without enough...
No - loads registered as Arsenal members and simply bought tickets from the club according to a pal - there was nothing to stop them doing it and no previous purchase history was necessary for this game.
Arsenal ST pal of mine said loads of them had got Red Membership (lowest level of club membership) then simply bought tickets online legitimately, hence the away fans being spread all over the ground. Club didn't pick up on the surge of new applications with German names from German ip addresses...