By my reading you wouldn't even need to fly. The Ts&Cs only say they will be taken back if you "request a refund". If you no show you won't be getting a refund.
Also, if you book, have them deposited in 10 days, spend them before the flight date, then don't show what are they doing to do? Give you a -9k Avios balance?
Seems badly thought out to me.