For the non-attendance issue, the main bulk of the cheapest ones are at the back of SS3. If they try to sell on the ticket exchange then they would struggle, as most tickets on sale are around the same price for match day. For the popular matches they would not use the exchange to get the £17 back 2 months later.
Put the tickets at the back of SS3 up and people will not buy them.
If the club wants to ensure as many seats are full as possible then they should get rid of 9320 which always looks half empty,