The club can't do anything about individual non-attending season ticket holders. However, I do agree with PB that it seems to be the same batches of seats in the North Stand that are empty most weeks - I was under the impression that City allocate some tickets to sports clubs, etc, in that area of the ground for league games so if they're not going to use them for a particular game then I don't see why they can't inform the club in advance and then they can be put on sale. Surely these groups know whether they're going to take up these seats or not and if they're not going to bother telling the club then City themselves should be on to them about it. Saturday's match was announced as a sell out on the OS so some City fans have missed out.
As for the jibes in that Mail article and in the comments section, it just sums up how ignorant and thick some of the wankers commenting are. They're focusing on one tier of one stand in a 55,000 capacity stadium and there were no more than a couple of hundred or so empty seats in it. The rest of the ground was pretty much packed save for the odd empty here and there plus the usual ones in the director's box and hospitality areas so any dick saying that there were 20,000 empty seats or whatever needs to give their heads a fucking wobble. You know it's a sell out when the corner blocks in the 3rd tier of the East and West stands are full - which they were on Saturday - as those tend to be the last seats to sell. Watching the brief highlights package on the OS and there's a great shot from behind Schmeichel's goal in about the 53rd minute which shows the whole of the South Stand at the other end of the pitch plus part of the East and st Stand. Save for a few empties in the hospitality section of South Stand tier 2, it's fucking rammed. I suppose at least the club aren't arsed about our empties being in full view of the TV cameras, whereas the Trafford Ministry of Truth makes sure most of theirs are well out of sight!