1975, John Eryl Hall Williams,Changing Prisons, page81:
[…] has had a 'K.B.' (knock-back) by being turned down for parole is something which the prison staff have had to learn to deal with[…]
1989, Michael Bettsworth,Marking Time: A Prison Memoir, page160:
My subsequent misconduct in prison had many inmate friends telling me that I would receive a knock-back.[…] At least I feel the wheels are rolling onwards and if I get aKB I am passing time.