When people pass them onto a mate there is very often a reciprocal financial transaction involved. I know of one such large group where this happens for every game with £25 being the acknowledged going rate.
(Note to Albion supporter services: I have clearly NEVER done this myself as it's against the law, the rules and I'd like to still go to games.)
Indeed but I never mentioned money. Club seems go after those advertising tickets as obviously there is no way to regulate informal sharing like that. Not saying it is a good thing just trying to point out that informal sharing isn't at threat. Personally some sort of sanctioned club exchange (where buyer has to supply their fan number & have a purchase history) would be ideal.