I agree, but the club could argue it costs them money. If you can't go, why should they let you hand it to a family member when they could make a tenner out of an on-line resale to somebody you don't know?
I guess if a corporate ticket just says 'corporate' then they'll let the holder through. 'Normal' tickets, and season tickets, I believe have names printed on them.
I wasn't there so can't confirm but I heard they were checking IDs at some away games towards the end of last season - QPR was one...
Surely the more prevalent this is, the more they'll start IDing everybody who walks through the turnstiles - leading to BANS coming for anyone who loaned their season ticket to their elderly father for one midweek game against Stoke.
Can they ask the re-sale site to confirm exactly which seats they are? If so I imagine it's fairly easy to start banning whoever 'officially' owns the ticket (and cancelling these tickets).
Maybe not in the site's interest to give out that info though.