I'm surprised more clubs haven't followed Man U's stance on ST holders not using tickets.
If you cannot make the game you have to let them know and they re-sell the ticket for that game. I believe they are VERY harsh and often punish people. For example i'm pretty sure as a Man U ST holder you have to go to cup games (at extra cost) or risk losing your home ticket for the next game. But don't quote me on that, something I heard way back from a friend who travels from Worthing for every home game.
But I believe it is your ST you've paid for it so do what you want. But something does need to be done about the thousands of empty seats at home game sell outs.
They certainly need to do something like this. We are in the incredible position where the season ticket holders and waiting list total count is so high that we'd potentially break our all time highest Goldstone gate most games next season. With that in mind, spare tickets are going to be like rocking horse shìt and I do think that fans who hold season tickets need to realise they are the privileged ones. I know they earnt the right to hold those tickets, but between the club and its fans, there should be no excuse for empty seats in these circumstances all the while we are in the top flight.