There are several ways of looking at this. I have been a voluntary member of the cup tkt scheme for a few years now. It means I get my own seat at all games and when it comes to matches with a big demand, cup finals etc, big away games etc, I always qualify because I've bought all the tkts.
In the old days at United, and possibly still at other clubs, a season tkt used to include the cup matches too, obviously at a higher price, and the new Glazer directive is simply returning to these days.
I don't think it's that unreasonable. If anyone wants to, and can afford to, travel to all the home league games, then it's not much of a stretch to buttume they'll want to see FA cup and CL games too. And in any case, the cup tkts come as simple match tickets, not like the season tkt in a book, and are therefore easy to pbutt on, or sell on, if you can't or don't want to make a particular game.
It's hardly ripping fans off to guarantee them tkts to see the first team play in cup competitions.
I have no time for the Glazers and hope they won't be around for long, but this scheme doesn't really have a victim as far as I can see.