I know - that's my point. Stopping sales to 'new' fans without a history for security related reasons doesn't match with letting anyone walk off the street to buy a ticket in the away end.
It is the same for home fans, I believe, using the 'print at home' feature, although I'm sure you can collect a ticket too if required.
I really don't get the ticket sale policy. There's a decent chance that people may have looked earlier in the week for, say, a group of 4. They'd have been...