1 of the issues they have put no thought into is people who buy tickets together, eg in members sale and auto cup, plus those lucky enough to get aways. You would never forward a ticket to these people but need them on friends and family so you can buy them together.
this could take up a big proportion of friends and family and they should have created 2 lists-1 who you can buy with and 1 you can forward to (which could be less than 18 if you had first list you can buy with)