Touts cannot account for thousands surely, the lads on Avenell Road and Drayton Park who kindly offer to “buy or sell any spare tickets”. There is normally 5-10 of them, even if their numbers multiplied that is impressive business by them.
I read earlier about a spike in club memberships originating from Germany. Now it was in a Guardian piece which at other times was a little silly so not sure how much faith to put in it.